C++ Mat3::TransformPoint方法代码示例

void SpriteBatch::DrawAgent(Agent* a_agent)
{

	Vec2 pos = a_agent->m_pos;

	float width		= (float)m_agentWidth;
	float height	= (float)m_agentHeight;

	int xOff = (int)width	/ 2;
	int yOff = (int)height	/ 2;

	Vec2 tl = Vec2(-xOff,			-yOff);
	Vec2 tr = Vec2(xOff ,			-yOff);
	Vec2 br = Vec2(-xOff,			yOff);
	Vec2 bl = Vec2(xOff ,			yOff);	

	float rot = Vec2(0,1).GetAngleBetween(a_agent->m_heading);

	//create matrix for start point
	Mat3 rotMat; 	
	rotMat.Rotate(rot + 3.141592654);
	rotMat.SetTranslation(pos);


	//set the 4 vert points to correct rotation
	tl = rotMat.TransformPoint(tl);
	tr = rotMat.TransformPoint(tr);
	br = rotMat.TransformPoint(br);
	bl = rotMat.TransformPoint(bl);	


	processSprite(&tl, &tr, &bl, &br, m_agentIBO, m_agentVBO, m_texID_agent, SPRITE_COLOUR_WHITE);
}

//Draw Line
void SpriteBatch::DrawLine(Vec2 a_start, Vec2 a_end, SPRITE_COLOUR a_col, float a_width)
{
	//width used to offsetting
	float width;

	if(a_width > 0)
		width = a_width;
	else
		width = (float)m_line_width / 2;	

	//width override for debugging
	//width = 50;

	float size = (a_start - a_end).Length();

	Vec2 origin = Vec2(-width / 2, 0);

	//set the line around the zero point with the pivot
	//at the top center (0,0)
	//oriented for rotation zero along the x axis
	Vec2 tl = Vec2(0,					0) + origin;
	Vec2 tr = Vec2(width,				0) + origin;
	Vec2 br = Vec2(0,				size)  + origin;
	Vec2 bl = Vec2(width,			size)  + origin;

	//get difference normalised
//	Vec2 diff = Vec2(a_end.x - a_start.x, a_end.y - a_start.y).GetNormalised();

	Vec2 diff = (a_start - a_end).GetNormalised();


	float rot = Vec2(0,1).GetAngleBetween(diff);

	//create matrix for start point
	Mat3 rotMat; 	
	rotMat.Rotate(rot + 3.141592654);
	rotMat.SetTranslation(a_start);
		

	//transform line start point
	tl = rotMat.TransformPoint(tl);
	tr = rotMat.TransformPoint(tr);

	//transform line end point
	br = rotMat.TransformPoint(br);
	bl = rotMat.TransformPoint(bl);

	processSprite(&tl, &tr, &bl, &br, m_lineIBO, m_lineVBO, m_texID_line, a_col);
}

void SpriteBatch::DrawSprite(unsigned int VBO, unsigned int IBO, unsigned int programID, unsigned int textureID , unsigned int projectionLoc, float *projectionMat, Mat3 &matrix, float a_width, float a_height, int rotatePoint, Vec2 a_pivot)
{
	//make sure we are drawing the current width of the object multiplied against the scale
	//otherwise changing the scale of the Mat3 isn't taken into account when drawing.
	float width = a_width * matrix.GetRightScale();
	float height = a_height * matrix.GetUpScale();

	Vec2 tl = Vec2(0,				 0)		+ a_pivot;
	Vec2 tr = Vec2(width,			 0)		+ a_pivot;
	Vec2 br = Vec2(0,			height)		+ a_pivot;
	Vec2 bl = Vec2(width,		height)		+ a_pivot;

	//set the 4 vert points to correct rotation
	tl = matrix.TransformPoint(tl);
	tr = matrix.TransformPoint(tr);
	br = matrix.TransformPoint(br);
	bl = matrix.TransformPoint(bl);


	Vertex vertexData[4] = 
	{
		Vertex(tl.x, tl.y,   1.0f, 1.0f, 1.0f, 1.0f,		 0.0f, 0.0f),
		Vertex(tr.x, tr.y,   1.0f, 1.0f, 1.0f, 1.0f,		 1.0f, 0.0f),
		Vertex(bl.x, bl.y,   1.0f, 1.0f, 1.0f, 1.0f,		 1.0f, 1.0f),
		Vertex(br.x, br.y,   1.0f, 1.0f, 1.0f, 1.0f,		 0.0f, 1.0f)
	};
	

	GLubyte indices[6] = 
	{
		0, 1, 2,	// first triangle
		0, 2, 3		// second triangle
	};

	glUseProgram(programID);

	//std::cout << glGetError() << std::endl;

	// bind our texture to active texture 0...
	glActiveTexture(GL_TEXTURE1);
	glBindTexture(GL_TEXTURE_2D, textureID);
	int textureLocation = glGetUniformLocation(programID, "myTextureSampler");
	glUniform1i(textureLocation , 1 );
	
	//send our orthographic projection info to the shader
	glUniformMatrix4fv(projectionLoc, 1, GL_FALSE, projectionMat);
	

	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IBO);
	
	//allocate space for vertices on the graphics card
	glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex)*4, vertexData, GL_STREAM_DRAW);
	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLubyte)*6, indices, GL_STREAM_DRAW);

	//enable the vertex array state, since we're sending in an array of vertices
	glEnableVertexAttribArray(0);
	glEnableVertexAttribArray(1);
	glEnableVertexAttribArray(2);

	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), 0); 
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)16);
	glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)32);
	//glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)(sizeof(float)*8));
		
	glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, NULL);
//	glDrawArrays(GL_QUADS, 0, 4);
	

	glBindBuffer(GL_ARRAY_BUFFER, 0);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
	glBindTexture(GL_TEXTURE_2D, 0);
	
	glUseProgram(0);
	

	//debug collision circles by displaying them
	//note that collision code should match this method for positions collision circles to be correct
	
	//create a posiiton around the world 0 point for the centre of the object to transform from
//	Vec2 drawPos = Vec2((width / 2) + a_pivot.x, (height / 2) + a_pivot.y);
//
//	//transform the circle point to where it needs to go
//	drawPos = matrix.TransformPoint(drawPos);
//
//	float radius = getRadius(width, height, matrix.GetRightScale());
//	//draw the circle
//	DrawCircle(drawPos.x, drawPos.y,  radius, 12, projectionLoc, projectionMat);
	
//	
}