C++ GLContext::fBindFramebuffer方法代码示例

void
GLBlitTextureImageHelper::SetBlitFramebufferForDestTexture(GLuint aTexture)
{
    GLContext *gl = mCompositor->gl();
    if (!mBlitFramebuffer) {
        gl->fGenFramebuffers(1, &mBlitFramebuffer);
    }

    gl->fBindFramebuffer(LOCAL_GL_FRAMEBUFFER, mBlitFramebuffer);
    gl->fFramebufferTexture2D(LOCAL_GL_FRAMEBUFFER,
                               LOCAL_GL_COLOR_ATTACHMENT0,
                               LOCAL_GL_TEXTURE_2D,
                               aTexture,
                               0);

    GLenum result = gl->fCheckFramebufferStatus(LOCAL_GL_FRAMEBUFFER);
    if (aTexture && (result != LOCAL_GL_FRAMEBUFFER_COMPLETE)) {
        nsAutoCString msg;
        msg.AppendLiteral("Framebuffer not complete -- error 0x");
        msg.AppendInt(result, 16);
        // Note: if you are hitting this, it is likely that
        // your texture is not texture complete -- that is, you
        // allocated a texture name, but didn't actually define its
        // size via a call to TexImage2D.
        NS_RUNTIMEABORT(msg.get());
    }
}

//.........这里部分代码省略.........
        // this tile is not part of the destination rectangle aDstRect
        if (dstSubRect.IsEmpty())
            continue;

        // (*) transform the rect of this tile into the rectangle defined by aSrcRect...
        nsIntRect dstInSrcRect(dstSubRect);
        dstInSrcRect.MoveBy(-aDstRect.TopLeft());
        // ...which might be of different size, hence scale accordingly
        dstInSrcRect.ScaleRoundOut(1.0f / blitScaleX, 1.0f / blitScaleY);
        dstInSrcRect.MoveBy(aSrcRect.TopLeft());

        SetBlitFramebufferForDestTexture(aDst->GetTextureID());
        UseBlitProgram();

        aSrc->BeginBigImageIteration();
        // now iterate over all tiles in the source Image...
        do {
            // calculate portion of the source tile that is in the source rect
            nsIntRect srcSubRect;
            nsIntRect srcTextureRect = ThebesIntRect(aSrc->GetTileRect());
            srcSubRect.IntersectRect(aSrcRect, srcTextureRect);

            // this tile is not part of the source rect
            if (srcSubRect.IsEmpty()) {
                continue;
            }
            // calculate intersection of source rect with destination rect
            srcSubRect.IntersectRect(srcSubRect, dstInSrcRect);
            // this tile does not overlap the current destination tile
            if (srcSubRect.IsEmpty()) {
                continue;
            }
            // We now have the intersection of
            //     the current source tile
            // and the desired source rectangle
            // and the destination tile
            // and the desired destination rectange
            // in destination space.
            // We need to transform this back into destination space, inverting the transform from (*)
            nsIntRect srcSubInDstRect(srcSubRect);
            srcSubInDstRect.MoveBy(-aSrcRect.TopLeft());
            srcSubInDstRect.ScaleRoundOut(blitScaleX, blitScaleY);
            srcSubInDstRect.MoveBy(aDstRect.TopLeft());

            // we transform these rectangles to be relative to the current src and dst tiles, respectively
            nsIntSize srcSize = srcTextureRect.Size();
            nsIntSize dstSize = dstTextureRect.Size();
            srcSubRect.MoveBy(-srcTextureRect.x, -srcTextureRect.y);
            srcSubInDstRect.MoveBy(-dstTextureRect.x, -dstTextureRect.y);

            float dx0 = 2.0f * float(srcSubInDstRect.x) / float(dstSize.width) - 1.0f;
            float dy0 = 2.0f * float(srcSubInDstRect.y) / float(dstSize.height) - 1.0f;
            float dx1 = 2.0f * float(srcSubInDstRect.x + srcSubInDstRect.width) / float(dstSize.width) - 1.0f;
            float dy1 = 2.0f * float(srcSubInDstRect.y + srcSubInDstRect.height) / float(dstSize.height) - 1.0f;
            ScopedViewportRect autoViewportRect(gl, 0, 0, dstSize.width, dstSize.height);

            RectTriangles rects;

            nsIntSize realTexSize = srcSize;
            if (!CanUploadNonPowerOfTwo(gl)) {
                realTexSize = nsIntSize(gfx::NextPowerOfTwo(srcSize.width),
                                        gfx::NextPowerOfTwo(srcSize.height));
            }

            if (aSrc->GetWrapMode() == LOCAL_GL_REPEAT) {
                rects.addRect(/* dest rectangle */
                        dx0, dy0, dx1, dy1,
                        /* tex coords */
                        srcSubRect.x / float(realTexSize.width),
                        srcSubRect.y / float(realTexSize.height),
                        srcSubRect.XMost() / float(realTexSize.width),
                        srcSubRect.YMost() / float(realTexSize.height));
            } else {
                DecomposeIntoNoRepeatTriangles(srcSubRect, realTexSize, rects);

                // now put the coords into the d[xy]0 .. d[xy]1 coordinate space
                // from the 0..1 that it comes out of decompose
                InfallibleTArray<RectTriangles::coord>& coords = rects.vertCoords();

                for (unsigned int i = 0; i < coords.Length(); ++i) {
                    coords[i].x = (coords[i].x * (dx1 - dx0)) + dx0;
                    coords[i].y = (coords[i].y * (dy1 - dy0)) + dy0;
                }
            }

            ScopedBindTextureUnit autoTexUnit(gl, LOCAL_GL_TEXTURE0);
            ScopedBindTexture autoTex(gl, aSrc->GetTextureID());
            ScopedVertexAttribPointer autoAttrib0(gl, 0, 2, LOCAL_GL_FLOAT, LOCAL_GL_FALSE, 0, 0, rects.vertCoords().Elements());
            ScopedVertexAttribPointer autoAttrib1(gl, 1, 2, LOCAL_GL_FLOAT, LOCAL_GL_FALSE, 0, 0, rects.texCoords().Elements());

            gl->fDrawArrays(LOCAL_GL_TRIANGLES, 0, rects.elements());

        } while (aSrc->NextTile());
    } while (aDst->NextTile());

    // unbind the previous texture from the framebuffer
    SetBlitFramebufferForDestTexture(0);

    gl->fBindFramebuffer(LOCAL_GL_FRAMEBUFFER, savedFb);
}