C++ GLES_RenderData类代码示例

SDL_Renderer *
GLES_CreateRenderer(SDL_Window * window, Uint32 flags)
{

    SDL_Renderer *renderer;
    GLES_RenderData *data;
    GLint value;
    Uint32 windowFlags;
    
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 1);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);
    
    windowFlags = SDL_GetWindowFlags(window);
    if (!(windowFlags & SDL_WINDOW_OPENGL)) {
        if (SDL_RecreateWindow(window, windowFlags | SDL_WINDOW_OPENGL) < 0) {
            /* Uh oh, better try to put it back... */
            SDL_RecreateWindow(window, windowFlags);
            return NULL;
        }
    }

    renderer = (SDL_Renderer *) SDL_calloc(1, sizeof(*renderer));
    if (!renderer) {
        SDL_OutOfMemory();
        return NULL;
    }

    data = (GLES_RenderData *) SDL_calloc(1, sizeof(*data));
    if (!data) {
        GLES_DestroyRenderer(renderer);
        SDL_OutOfMemory();
        return NULL;
    }

    renderer->WindowEvent = GLES_WindowEvent;
    renderer->CreateTexture = GLES_CreateTexture;
    renderer->UpdateTexture = GLES_UpdateTexture;
    renderer->LockTexture = GLES_LockTexture;
    renderer->UnlockTexture = GLES_UnlockTexture;
    renderer->SetRenderTarget = GLES_SetRenderTarget;
    renderer->UpdateViewport = GLES_UpdateViewport;
    renderer->RenderClear = GLES_RenderClear;
    renderer->RenderDrawPoints = GLES_RenderDrawPoints;
    renderer->RenderDrawLines = GLES_RenderDrawLines;
    renderer->RenderFillRects = GLES_RenderFillRects;
    renderer->RenderCopy = GLES_RenderCopy;
    renderer->RenderReadPixels = GLES_RenderReadPixels;
    renderer->RenderPresent = GLES_RenderPresent;
    renderer->DestroyTexture = GLES_DestroyTexture;
    renderer->DestroyRenderer = GLES_DestroyRenderer;
    renderer->info = GLES_RenderDriver.info;
    renderer->info.flags = SDL_RENDERER_ACCELERATED;
    renderer->driverdata = data;
    renderer->window = window;

    data->context = SDL_GL_CreateContext(window);
    if (!data->context) {
        GLES_DestroyRenderer(renderer);
        return NULL;
    }
    if (SDL_GL_MakeCurrent(window, data->context) < 0) {
        GLES_DestroyRenderer(renderer);
        return NULL;
    }

    if (GLES_LoadFunctions(data) < 0) {
        GLES_DestroyRenderer(renderer);
        return NULL;
    }

    if (flags & SDL_RENDERER_PRESENTVSYNC) {
        SDL_GL_SetSwapInterval(1);
    } else {
        SDL_GL_SetSwapInterval(0);
    }
    if (SDL_GL_GetSwapInterval() > 0) {
        renderer->info.flags |= SDL_RENDERER_PRESENTVSYNC;
    }

#if SDL_VIDEO_DRIVER_PANDORA
    data->GL_OES_draw_texture_supported = SDL_FALSE;
    data->useDrawTexture = SDL_FALSE;
#else
    if (SDL_GL_ExtensionSupported("GL_OES_draw_texture")) {
        data->GL_OES_draw_texture_supported = SDL_TRUE;
        data->useDrawTexture = SDL_TRUE;
    } else {
        data->GL_OES_draw_texture_supported = SDL_FALSE;
        data->useDrawTexture = SDL_FALSE;
    }
#endif

    data->glGetIntegerv(GL_MAX_TEXTURE_SIZE, &value);
    renderer->info.max_texture_width = value;
    data->glGetIntegerv(GL_MAX_TEXTURE_SIZE, &value);
    renderer->info.max_texture_height = value;

    if (SDL_GL_ExtensionSupported("GL_OES_framebuffer_object")) {
        data->GL_OES_framebuffer_object_supported = SDL_TRUE;
        renderer->info.flags |= SDL_RENDERER_TARGETTEXTURE;
//.........这里部分代码省略.........

static int
GLES_CreateTexture(SDL_Renderer * renderer, SDL_Texture * texture)
{
    GLES_RenderData *renderdata = (GLES_RenderData *) renderer->driverdata;
    GLES_TextureData *data;
    GLint internalFormat;
    GLenum format, type;
    int texture_w, texture_h;
    GLenum scaleMode;
    GLenum result;

    GLES_ActivateRenderer(renderer);

    switch (texture->format) {
    case SDL_PIXELFORMAT_ABGR8888:
        internalFormat = GL_RGBA;
        format = GL_RGBA;
        type = GL_UNSIGNED_BYTE;
        break;
    default:
        return SDL_SetError("Texture format not supported");
    }

    data = (GLES_TextureData *) SDL_calloc(1, sizeof(*data));
    if (!data) {
        return SDL_OutOfMemory();
    }

    if (texture->access == SDL_TEXTUREACCESS_STREAMING) {
        data->pitch = texture->w * SDL_BYTESPERPIXEL(texture->format);
        data->pixels = SDL_calloc(1, texture->h * data->pitch);
        if (!data->pixels) {
            SDL_free(data);
            return SDL_OutOfMemory();
        }
    }

    
    if (texture->access == SDL_TEXTUREACCESS_TARGET) {
        if (!renderdata->GL_OES_framebuffer_object_supported) {
            SDL_free(data);
            return SDL_SetError("GL_OES_framebuffer_object not supported");
        }
        data->fbo = GLES_GetFBO(renderer->driverdata, texture->w, texture->h);
    } else {
        data->fbo = NULL;
    }
    

    renderdata->glGetError();
    renderdata->glEnable(GL_TEXTURE_2D);
    renderdata->glGenTextures(1, &data->texture);
    result = renderdata->glGetError();
    if (result != GL_NO_ERROR) {
        SDL_free(data);
        return GLES_SetError("glGenTextures()", result);
    }

    data->type = GL_TEXTURE_2D;
    /* no NPOV textures allowed in OpenGL ES (yet) */
    texture_w = power_of_2(texture->w);
    texture_h = power_of_2(texture->h);
    data->texw = (GLfloat) texture->w / texture_w;
    data->texh = (GLfloat) texture->h / texture_h;

    data->format = format;
    data->formattype = type;
    scaleMode = GetScaleQuality();
    renderdata->glBindTexture(data->type, data->texture);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_MIN_FILTER, scaleMode);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_MAG_FILTER, scaleMode);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    renderdata->glTexImage2D(data->type, 0, internalFormat, texture_w,
                             texture_h, 0, format, type, NULL);
    renderdata->glDisable(GL_TEXTURE_2D);

    result = renderdata->glGetError();
    if (result != GL_NO_ERROR) {
        SDL_free(data);
        return GLES_SetError("glTexImage2D()", result);
    }
    
    texture->driverdata = data;
    return 0;
}

static int
GLES_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
                const SDL_Rect * srcrect, const SDL_FRect * dstrect)
{
    GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;
    GLES_TextureData *texturedata = (GLES_TextureData *) texture->driverdata;
    GLfloat minx, miny, maxx, maxy;
    GLfloat minu, maxu, minv, maxv;
    GLfloat vertices[8];
    GLfloat texCoords[8];

    GLES_ActivateRenderer(renderer);

    data->glEnable(GL_TEXTURE_2D);

    data->glBindTexture(texturedata->type, texturedata->texture);

    if (texture->modMode) {
        GLES_SetColor(data, texture->r, texture->g, texture->b, texture->a);
    } else {
        GLES_SetColor(data, 255, 255, 255, 255);
    }

    GLES_SetBlendMode(data, texture->blendMode);

    GLES_SetTexCoords(data, SDL_TRUE);

    if (data->GL_OES_draw_texture_supported && data->useDrawTexture) {
        /* this code is a little funny because the viewport is upside down vs SDL's coordinate system */
        GLint cropRect[4];
        int w, h;
        SDL_Window *window = renderer->window;

        SDL_GetWindowSize(window, &w, &h);
        if (renderer->target) {
            cropRect[0] = srcrect->x;
            cropRect[1] = srcrect->y;
            cropRect[2] = srcrect->w;
            cropRect[3] = srcrect->h;
            data->glTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_CROP_RECT_OES,
                                   cropRect);
            data->glDrawTexfOES(renderer->viewport.x + dstrect->x, renderer->viewport.y + dstrect->y, 0,
                                dstrect->w, dstrect->h);
        } else {
            cropRect[0] = srcrect->x;
            cropRect[1] = srcrect->y + srcrect->h;
            cropRect[2] = srcrect->w;
            cropRect[3] = -srcrect->h;
            data->glTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_CROP_RECT_OES,
                                   cropRect);
            data->glDrawTexfOES(renderer->viewport.x + dstrect->x,
                        h - (renderer->viewport.y + dstrect->y) - dstrect->h, 0,
                        dstrect->w, dstrect->h);
        }
    } else {

        minx = dstrect->x;
        miny = dstrect->y;
        maxx = dstrect->x + dstrect->w;
        maxy = dstrect->y + dstrect->h;

        minu = (GLfloat) srcrect->x / texture->w;
        minu *= texturedata->texw;
        maxu = (GLfloat) (srcrect->x + srcrect->w) / texture->w;
        maxu *= texturedata->texw;
        minv = (GLfloat) srcrect->y / texture->h;
        minv *= texturedata->texh;
        maxv = (GLfloat) (srcrect->y + srcrect->h) / texture->h;
        maxv *= texturedata->texh;

        vertices[0] = minx;
        vertices[1] = miny;
        vertices[2] = maxx;
        vertices[3] = miny;
        vertices[4] = minx;
        vertices[5] = maxy;
        vertices[6] = maxx;
        vertices[7] = maxy;

        texCoords[0] = minu;
        texCoords[1] = minv;
        texCoords[2] = maxu;
        texCoords[3] = minv;
        texCoords[4] = minu;
        texCoords[5] = maxv;
        texCoords[6] = maxu;
        texCoords[7] = maxv;

        data->glVertexPointer(2, GL_FLOAT, 0, vertices);
        data->glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
        data->glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    }
    data->glDisable(GL_TEXTURE_2D);

    return 0;
}

static int
GLES_RenderCopyEx(SDL_Renderer * renderer, SDL_Texture * texture,
                const SDL_Rect * srcrect, const SDL_FRect * dstrect,
                const double angle, const SDL_FPoint *center, const SDL_RendererFlip flip)
{

    GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;
    GLES_TextureData *texturedata = (GLES_TextureData *) texture->driverdata;
    GLfloat minx, miny, maxx, maxy;
    GLfloat minu, maxu, minv, maxv;
    GLfloat centerx, centery;
    GLfloat vertices[8];
    GLfloat texCoords[8];


    GLES_ActivateRenderer(renderer);

    data->glEnable(GL_TEXTURE_2D);

    data->glBindTexture(texturedata->type, texturedata->texture);

    if (texture->modMode) {
        GLES_SetColor(data, texture->r, texture->g, texture->b, texture->a);
    } else {
        GLES_SetColor(data, 255, 255, 255, 255);
    }

    GLES_SetBlendMode(data, texture->blendMode);

    GLES_SetTexCoords(data, SDL_TRUE);

    centerx = center->x;
    centery = center->y;

    /* Rotate and translate */
    data->glPushMatrix();
    data->glTranslatef(dstrect->x + centerx, dstrect->y + centery, 0.0f);
    data->glRotatef((GLfloat)angle, 0.0f, 0.0f, 1.0f);

    if (flip & SDL_FLIP_HORIZONTAL) {
        minx =  dstrect->w - centerx;
        maxx = -centerx;
    } else {
        minx = -centerx;
        maxx = dstrect->w - centerx;
    }

    if (flip & SDL_FLIP_VERTICAL) {
        miny = dstrect->h - centery;
        maxy = -centery;
    } else {
        miny = -centery;
        maxy = dstrect->h - centery;
    }

    minu = (GLfloat) srcrect->x / texture->w;
    minu *= texturedata->texw;
    maxu = (GLfloat) (srcrect->x + srcrect->w) / texture->w;
    maxu *= texturedata->texw;
    minv = (GLfloat) srcrect->y / texture->h;
    minv *= texturedata->texh;
    maxv = (GLfloat) (srcrect->y + srcrect->h) / texture->h;
    maxv *= texturedata->texh;

    vertices[0] = minx;
    vertices[1] = miny;
    vertices[2] = maxx;
    vertices[3] = miny;
    vertices[4] = minx;
    vertices[5] = maxy;
    vertices[6] = maxx;
    vertices[7] = maxy;

    texCoords[0] = minu;
    texCoords[1] = minv;
    texCoords[2] = maxu;
    texCoords[3] = minv;
    texCoords[4] = minu;
    texCoords[5] = maxv;
    texCoords[6] = maxu;
    texCoords[7] = maxv;
    data->glVertexPointer(2, GL_FLOAT, 0, vertices);
    data->glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
    data->glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    data->glPopMatrix();
    data->glDisable(GL_TEXTURE_2D);

    return 0;
}

SDL_Renderer *
GLES_CreateRenderer(SDL_Window * window, Uint32 flags)
{

    SDL_Renderer *renderer;
    GLES_RenderData *data;
    GLint value;
    Uint32 window_flags;
    int profile_mask = 0, major = 0, minor = 0;
    SDL_bool changed_window = SDL_FALSE;

    SDL_GL_GetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, &profile_mask);
    SDL_GL_GetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, &major);
    SDL_GL_GetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, &minor);

    window_flags = SDL_GetWindowFlags(window);
    if (!(window_flags & SDL_WINDOW_OPENGL) ||
        profile_mask != SDL_GL_CONTEXT_PROFILE_ES || major != RENDERER_CONTEXT_MAJOR || minor != RENDERER_CONTEXT_MINOR) {

        changed_window = SDL_TRUE;
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, RENDERER_CONTEXT_MAJOR);
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, RENDERER_CONTEXT_MINOR);

        if (SDL_RecreateWindow(window, window_flags | SDL_WINDOW_OPENGL) < 0) {
            goto error;
        }
    }

    renderer = (SDL_Renderer *) SDL_calloc(1, sizeof(*renderer));
    if (!renderer) {
        SDL_OutOfMemory();
        goto error;
    }

    data = (GLES_RenderData *) SDL_calloc(1, sizeof(*data));
    if (!data) {
        GLES_DestroyRenderer(renderer);
        SDL_OutOfMemory();
        goto error;
    }

    renderer->WindowEvent = GLES_WindowEvent;
    renderer->GetOutputSize = GLES_GetOutputSize;
    renderer->CreateTexture = GLES_CreateTexture;
    renderer->UpdateTexture = GLES_UpdateTexture;
    renderer->LockTexture = GLES_LockTexture;
    renderer->UnlockTexture = GLES_UnlockTexture;
    renderer->SetRenderTarget = GLES_SetRenderTarget;
    renderer->UpdateViewport = GLES_UpdateViewport;
    renderer->UpdateClipRect = GLES_UpdateClipRect;
    renderer->RenderClear = GLES_RenderClear;
    renderer->RenderDrawPoints = GLES_RenderDrawPoints;
    renderer->RenderDrawLines = GLES_RenderDrawLines;
    renderer->RenderFillRects = GLES_RenderFillRects;
    renderer->RenderCopy = GLES_RenderCopy;
    renderer->RenderCopyEx = GLES_RenderCopyEx;
    renderer->RenderReadPixels = GLES_RenderReadPixels;
    renderer->RenderPresent = GLES_RenderPresent;
    renderer->DestroyTexture = GLES_DestroyTexture;
    renderer->DestroyRenderer = GLES_DestroyRenderer;
    renderer->GL_BindTexture = GLES_BindTexture;
    renderer->GL_UnbindTexture = GLES_UnbindTexture;
    renderer->info = GLES_RenderDriver.info;
    renderer->info.flags = SDL_RENDERER_ACCELERATED;
    renderer->driverdata = data;
    renderer->window = window;

    data->context = SDL_GL_CreateContext(window);
    if (!data->context) {
        GLES_DestroyRenderer(renderer);
        goto error;
    }
    if (SDL_GL_MakeCurrent(window, data->context) < 0) {
        GLES_DestroyRenderer(renderer);
        goto error;
    }

    if (GLES_LoadFunctions(data) < 0) {
        GLES_DestroyRenderer(renderer);
        goto error;
    }

    if (flags & SDL_RENDERER_PRESENTVSYNC) {
        SDL_GL_SetSwapInterval(1);
    } else {
        SDL_GL_SetSwapInterval(0);
    }
    if (SDL_GL_GetSwapInterval() > 0) {
        renderer->info.flags |= SDL_RENDERER_PRESENTVSYNC;
    }

#if SDL_VIDEO_DRIVER_PANDORA
    data->GL_OES_draw_texture_supported = SDL_FALSE;
    data->useDrawTexture = SDL_FALSE;
#else
    if (SDL_GL_ExtensionSupported("GL_OES_draw_texture")) {
        data->GL_OES_draw_texture_supported = SDL_TRUE;
        data->useDrawTexture = SDL_TRUE;
    } else {
//.........这里部分代码省略.........

static int
GLES_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
                const SDL_Rect * srcrect, const SDL_Rect * dstrect)
{

    GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;
    GLES_TextureData *texturedata = (GLES_TextureData *) texture->driverdata;
    int minx, miny, maxx, maxy;
    GLfloat minu, maxu, minv, maxv;
    int i;
    void *temp_buffer;          /* used for reformatting dirty rect pixels */
    void *temp_ptr;

    data->glEnable(GL_TEXTURE_2D);

    if (texturedata->dirty.list) {
        SDL_DirtyRect *dirty;
        void *pixels;
        int bpp = SDL_BYTESPERPIXEL(texture->format);
        int pitch = texturedata->pitch;

        SetupTextureUpdate(data, texture, pitch);

        data->glBindTexture(texturedata->type, texturedata->texture);
        for (dirty = texturedata->dirty.list; dirty; dirty = dirty->next) {
            SDL_Rect *rect = &dirty->rect;
            pixels =
                (void *) ((Uint8 *) texturedata->pixels + rect->y * pitch +
                          rect->x * bpp);
            /*      There is no GL_UNPACK_ROW_LENGTH in OpenGLES 
               we must do this reformatting ourselves(!)

               maybe it'd be a good idea to keep a temp buffer around
               for this purpose rather than allocating it each time
             */
            if( rect->x == 0 && rect->w * bpp == pitch ) {
                temp_buffer = pixels; /* Updating whole texture, no need to reformat */
            } else {
                temp_buffer = SDL_malloc(rect->w * rect->h * bpp);
                temp_ptr = temp_buffer;
                for (i = 0; i < rect->h; i++) {
                    SDL_memcpy(temp_ptr, pixels, rect->w * bpp);
                    temp_ptr += rect->w * bpp;
                    pixels += pitch;
                }
            }

            data->glTexSubImage2D(texturedata->type, 0, rect->x, rect->y,
                                  rect->w, rect->h, texturedata->format,
                                  texturedata->formattype, temp_buffer);

            if( temp_buffer != pixels ) {
                SDL_free(temp_buffer);
            }
        }
        SDL_ClearDirtyRects(&texturedata->dirty);
    }

    data->glBindTexture(texturedata->type, texturedata->texture);

    if (texture->modMode) {
        data->glColor4f((GLfloat) texture->r * inv255f,
                        (GLfloat) texture->g * inv255f,
                        (GLfloat) texture->b * inv255f,
                        (GLfloat) texture->a * inv255f);
    } else {
        data->glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
    }

    GLES_SetBlendMode(data, texture->blendMode, 0);

    switch (texture->scaleMode) {
    case SDL_TEXTURESCALEMODE_NONE:
    case SDL_TEXTURESCALEMODE_FAST:
        data->glTexParameteri(texturedata->type, GL_TEXTURE_MIN_FILTER,
                              GL_NEAREST);
        data->glTexParameteri(texturedata->type, GL_TEXTURE_MAG_FILTER,
                              GL_NEAREST);
        break;
    case SDL_TEXTURESCALEMODE_SLOW:
    case SDL_TEXTURESCALEMODE_BEST:
        data->glTexParameteri(texturedata->type, GL_TEXTURE_MIN_FILTER,
                              GL_LINEAR);
        data->glTexParameteri(texturedata->type, GL_TEXTURE_MAG_FILTER,
                              GL_LINEAR);
        break;
    }

    if (data->GL_OES_draw_texture_supported && data->useDrawTexture) {
        /* this code is a little funny because the viewport is upside down vs SDL's coordinate system */
        SDL_Window *window = renderer->window;
        GLint cropRect[4];
        cropRect[0] = srcrect->x;
        cropRect[1] = srcrect->y + srcrect->h;
        cropRect[2] = srcrect->w;
        cropRect[3] = -srcrect->h;
        data->glTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_CROP_RECT_OES,
                               cropRect);
        data->glDrawTexiOES(dstrect->x, window->h - dstrect->y - dstrect->h,
                            0, dstrect->w, dstrect->h);
//.........这里部分代码省略.........

static int
GLES_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
                const SDL_Rect * srcrect, const SDL_FRect * dstrect)
{
    GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;
    GLES_TextureData *texturedata = (GLES_TextureData *) texture->driverdata;
    GLfloat minx, miny, maxx, maxy;
    GLfloat minu, maxu, minv, maxv;
    GLfloat vertices[8];
    GLfloat texCoords[8];

    GLES_ActivateRenderer(renderer);

    data->glEnable(GL_TEXTURE_2D);

    data->glBindTexture(texturedata->type, texturedata->texture);

    if (texture->modMode) {
        GLES_SetColor(data, texture->r, texture->g, texture->b, texture->a);
    } else {
        GLES_SetColor(data, 255, 255, 255, 255);
    }

    GLES_SetBlendMode(data, texture->blendMode);

    GLES_SetTexCoords(data, SDL_TRUE);

    minx = dstrect->x;
    miny = dstrect->y;
    maxx = dstrect->x + dstrect->w;
    maxy = dstrect->y + dstrect->h;

    minu = (GLfloat) srcrect->x / texture->w;
    minu *= texturedata->texw;
    maxu = (GLfloat) (srcrect->x + srcrect->w) / texture->w;
    maxu *= texturedata->texw;
    minv = (GLfloat) srcrect->y / texture->h;
    minv *= texturedata->texh;
    maxv = (GLfloat) (srcrect->y + srcrect->h) / texture->h;
    maxv *= texturedata->texh;

    vertices[0] = minx;
    vertices[1] = miny;
    vertices[2] = maxx;
    vertices[3] = miny;
    vertices[4] = minx;
    vertices[5] = maxy;
    vertices[6] = maxx;
    vertices[7] = maxy;

    texCoords[0] = minu;
    texCoords[1] = minv;
    texCoords[2] = maxu;
    texCoords[3] = minv;
    texCoords[4] = minu;
    texCoords[5] = maxv;
    texCoords[6] = maxu;
    texCoords[7] = maxv;

    data->glVertexPointer(2, GL_FLOAT, 0, vertices);
    data->glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
    data->glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    data->glDisable(GL_TEXTURE_2D);

    return 0;
}

static int
GLES_CreateTexture(SDL_Renderer * renderer, SDL_Texture * texture)
{
    GLES_RenderData *renderdata = (GLES_RenderData *) renderer->driverdata;
    GLES_TextureData *data;
    GLint internalFormat;
    GLenum format, type;
    int texture_w, texture_h;
    GLenum result;

    switch (texture->format) {
    case SDL_PIXELFORMAT_BGR24:
        internalFormat = GL_RGB;
        format = GL_RGB;
        type = GL_UNSIGNED_BYTE;
        break;
    case SDL_PIXELFORMAT_ABGR8888:
        internalFormat = GL_RGBA;
        format = GL_RGBA;
        type = GL_UNSIGNED_BYTE;
        break;
    case SDL_PIXELFORMAT_BGR565:
        internalFormat = GL_RGB;
        format = GL_RGB;
        type = GL_UNSIGNED_SHORT_5_6_5;
        break;
    case SDL_PIXELFORMAT_ABGR1555:
        internalFormat = GL_RGBA;
        format = GL_RGBA;
        type = GL_UNSIGNED_SHORT_5_5_5_1;
        break;
    case SDL_PIXELFORMAT_ABGR4444:
        internalFormat = GL_RGBA;
        format = GL_RGBA;
        type = GL_UNSIGNED_SHORT_4_4_4_4;
        break;
    default:
        SDL_SetError("Unsupported by OpenGL ES texture format");
        return -1;
    }

    data = (GLES_TextureData *) SDL_calloc(1, sizeof(*data));
    if (!data) {
        SDL_OutOfMemory();
        return -1;
    }

    if (texture->access == SDL_TEXTUREACCESS_STREAMING) {
        data->pitch = texture->w * SDL_BYTESPERPIXEL(texture->format);
        data->pixels = SDL_malloc(texture->h * data->pitch);
        if (!data->pixels) {
            SDL_OutOfMemory();
            SDL_free(data);
            return -1;
        }
    }

    texture->driverdata = data;

    renderdata->glGetError();
    renderdata->glEnable(GL_TEXTURE_2D);
    renderdata->glGenTextures(1, &data->texture);

    data->type = GL_TEXTURE_2D;
    /* no NPOV textures allowed in OpenGL ES (yet) */
    texture_w = power_of_2(texture->w);
    texture_h = power_of_2(texture->h);
    data->texw = (GLfloat) texture->w / texture_w;
    data->texh = (GLfloat) texture->h / texture_h;

    data->format = format;
    data->formattype = type;
    renderdata->glBindTexture(data->type, data->texture);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_MIN_FILTER,
                                GL_NEAREST);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_MAG_FILTER,
                                GL_NEAREST);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_WRAP_S,
                                GL_CLAMP_TO_EDGE);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_WRAP_T,
                                GL_CLAMP_TO_EDGE);

    renderdata->glTexImage2D(data->type, 0, internalFormat, texture_w,
                             texture_h, 0, format, type, NULL);
    renderdata->glDisable(GL_TEXTURE_2D);

    result = renderdata->glGetError();
    if (result != GL_NO_ERROR) {
        GLES_SetError("glTexImage2D()", result);
        return -1;
    }
    return 0;
}

SDL_Renderer *
GLES_CreateRenderer(SDL_Window * window, Uint32 flags)
{

    SDL_Renderer *renderer;
    GLES_RenderData *data;
    GLint value;
    int doublebuffer;

    if (!(window->flags & SDL_WINDOW_OPENGL)) {
        if (SDL_RecreateWindow(window, window->flags | SDL_WINDOW_OPENGL) < 0) {
            return NULL;
        }
    }

    renderer = (SDL_Renderer *) SDL_calloc(1, sizeof(*renderer));
    if (!renderer) {
        SDL_OutOfMemory();
        return NULL;
    }

    data = (GLES_RenderData *) SDL_calloc(1, sizeof(*data));
    if (!data) {
        GLES_DestroyRenderer(renderer);
        SDL_OutOfMemory();
        return NULL;
    }

    renderer->ActivateRenderer = GLES_ActivateRenderer;
    renderer->DisplayModeChanged = GLES_DisplayModeChanged;
    renderer->CreateTexture = GLES_CreateTexture;
    renderer->QueryTexturePixels = GLES_QueryTexturePixels;
    renderer->SetTexturePalette = GLES_SetTexturePalette;
    renderer->GetTexturePalette = GLES_GetTexturePalette;
    renderer->SetTextureColorMod = GLES_SetTextureColorMod;
    renderer->SetTextureAlphaMod = GLES_SetTextureAlphaMod;
    renderer->SetTextureBlendMode = GLES_SetTextureBlendMode;
    renderer->SetTextureScaleMode = GLES_SetTextureScaleMode;
    renderer->UpdateTexture = GLES_UpdateTexture;
    renderer->LockTexture = GLES_LockTexture;
    renderer->UnlockTexture = GLES_UnlockTexture;
    renderer->DirtyTexture = GLES_DirtyTexture;
    renderer->RenderDrawPoints = GLES_RenderDrawPoints;
    renderer->RenderDrawLines = GLES_RenderDrawLines;
    renderer->RenderDrawRects = GLES_RenderDrawRects;
    renderer->RenderFillRects = GLES_RenderFillRects;
    renderer->RenderCopy = GLES_RenderCopy;
    renderer->RenderPresent = GLES_RenderPresent;
    renderer->DestroyTexture = GLES_DestroyTexture;
    renderer->DestroyRenderer = GLES_DestroyRenderer;
    renderer->info = GL_ES_RenderDriver.info;
    renderer->window = window;
    renderer->driverdata = data;

    renderer->info.flags =
        (SDL_RENDERER_PRESENTDISCARD | SDL_RENDERER_ACCELERATED);

#if defined(__QNXNTO__)
#if _NTO_VERSION<=641
    /* QNX's OpenGL ES implementation is broken regarding             */
    /* packed textures support, affected versions 6.3.2, 6.4.0, 6.4.1 */
    renderer->info.num_texture_formats = 2;
    renderer->info.texture_formats[0] = SDL_PIXELFORMAT_ABGR8888;
    renderer->info.texture_formats[1] = SDL_PIXELFORMAT_BGR24;
#endif /* _NTO_VERSION */
#endif /* __QNXNTO__ */

    if (GLES_LoadFunctions(data) < 0) {
        GLES_DestroyRenderer(renderer);
        return NULL;
    }

    data->context = SDL_GL_CreateContext(window);
    if (!data->context) {
        GLES_DestroyRenderer(renderer);
        return NULL;
    }
    if (SDL_GL_MakeCurrent(window, data->context) < 0) {
        GLES_DestroyRenderer(renderer);
        return NULL;
    }

    if (flags & SDL_RENDERER_PRESENTVSYNC) {
        SDL_GL_SetSwapInterval(1);
    } else {
        SDL_GL_SetSwapInterval(0);
    }
    if (SDL_GL_GetSwapInterval() > 0) {
        renderer->info.flags |= SDL_RENDERER_PRESENTVSYNC;
    }

    if (SDL_GL_GetAttribute(SDL_GL_DOUBLEBUFFER, &doublebuffer) == 0) {
        if (!doublebuffer) {
            renderer->info.flags |= SDL_RENDERER_SINGLEBUFFER;
        }
    }
#if SDL_VIDEO_DRIVER_PANDORA
    data->GL_OES_draw_texture_supported = SDL_FALSE;
    data->useDrawTexture = SDL_FALSE;
#else
//.........这里部分代码省略.........

static int
GLES_CreateTexture(SDL_Renderer * renderer, SDL_Texture * texture)
{
    GLES_RenderData *renderdata = (GLES_RenderData *) renderer->driverdata;
    GLES_TextureData *data;
    GLint internalFormat;
    GLenum format, type;
    int texture_w, texture_h;
    GLenum result;

    switch (texture->format) {
    case SDL_PIXELFORMAT_RGB24:
        internalFormat = GL_RGB;
        format = GL_RGB;
        type = GL_UNSIGNED_BYTE;
        break;
    case SDL_PIXELFORMAT_BGR888:
    case SDL_PIXELFORMAT_ABGR8888:
        internalFormat = GL_RGBA;
        format = GL_RGBA;
        type = GL_UNSIGNED_BYTE;
        break;
    case SDL_PIXELFORMAT_RGB565:
        internalFormat = GL_RGB;
        format = GL_RGB;
        type = GL_UNSIGNED_SHORT_5_6_5;
        break;
    case SDL_PIXELFORMAT_RGBA5551:
        internalFormat = GL_RGBA;
        format = GL_RGBA;
        type = GL_UNSIGNED_SHORT_5_5_5_1;
        break;
    case SDL_PIXELFORMAT_RGBA4444:
        internalFormat = GL_RGBA;
        format = GL_RGBA;
        type = GL_UNSIGNED_SHORT_4_4_4_4;
        break;
    default:
        SDL_SetError("Texture format %s not supported by OpenGL ES",
                     SDL_GetPixelFormatName(texture->format));
        return -1;
    }

    data = (GLES_TextureData *) SDL_calloc(1, sizeof(*data));
    if (!data) {
        SDL_OutOfMemory();
        return -1;
    }

    if (texture->access == SDL_TEXTUREACCESS_STREAMING) 
    {
        data->pitch = texture->w * SDL_BYTESPERPIXEL(texture->format);
        data->pixels = SDL_malloc(texture->h * data->pitch);
        if (!data->pixels) {
            SDL_OutOfMemory();
            SDL_free(data);
            return -1;
        }
    }

    texture->driverdata = data;

    renderdata->glGetError();
    renderdata->glEnable(GL_TEXTURE_2D);
    renderdata->glGenTextures(1, &data->texture);

    data->type = GL_TEXTURE_2D;
    /* no NPOV textures allowed in OpenGL ES (yet) */
    texture_w = power_of_2(texture->w);
    texture_h = power_of_2(texture->h);
    data->texw = (GLfloat) texture->w / texture_w;
    data->texh = (GLfloat) texture->h / texture_h;
    if( renderer->info.max_texture_width < texture_w || renderer->info.max_texture_height < texture_h )
        __android_log_print(ANDROID_LOG_WARN, "libSDL", "GLES: Allocated texture of size %dx%d which is bigger than largest possible device texture %dx%d",
                            texture_w, texture_h, renderer->info.max_texture_width, renderer->info.max_texture_height );
    else if( texture_w > 1024 || texture_h > 1024 )
        __android_log_print(ANDROID_LOG_WARN, "libSDL", "GLES: Allocated texture of size %dx%d which is bigger than 1024x1024 - this code will not work on HTC G1", texture_w, texture_h );

    data->format = format;
    data->formattype = type;
    renderdata->glBindTexture(data->type, data->texture);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_MIN_FILTER,
                                GL_NEAREST);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_MAG_FILTER,
                                GL_NEAREST);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_WRAP_S,
                                GL_CLAMP_TO_EDGE);
    renderdata->glTexParameteri(data->type, GL_TEXTURE_WRAP_T,
                                GL_CLAMP_TO_EDGE);

    renderdata->glTexImage2D(data->type, 0, internalFormat, texture_w,
                             texture_h, 0, format, type, NULL);
    renderdata->glDisable(GL_TEXTURE_2D);

    result = renderdata->glGetError();
    if (result != GL_NO_ERROR) {
        GLES_SetError("glTexImage2D()", result);
        return -1;
    }
    return 0;
//.........这里部分代码省略.........

static int
GLES_ActivateRenderer(SDL_Renderer * renderer)
{

    GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;
    SDL_Window *window = renderer->window;

    if (SDL_GL_MakeCurrent(window, data->context) < 0) {
        return -1;
    }

    /* Set up parameters for rendering */
    data->blendMode = -1;
    data->glDisable(GL_DEPTH_TEST);
    data->glDisable(GL_CULL_FACE);
    data->updateSize = SDL_TRUE;

    if (data->updateSize) {
        data->glMatrixMode(GL_PROJECTION);
        data->glLoadIdentity();
        data->glMatrixMode(GL_MODELVIEW);
        data->glLoadIdentity();
#if SDL_VIDEO_RENDER_RESIZE
        data->glViewport(0, 0, window->display->desktop_mode.w, window->display->desktop_mode.h);
        data->glOrthof(0.0, (GLfloat) window->display->desktop_mode.w, (GLfloat) window->display->desktop_mode.h,
                       0.0, 0.0, 1.0);
#else
        data->glViewport(0, 0, window->w, window->h);
        data->glOrthof(0.0, (GLfloat) window->w, (GLfloat) window->h, 
                       0.0, 0.0, 1.0);
#endif
        data->updateSize = SDL_FALSE;
    }
    return 0;
}