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Bug fix: correct the calculation for texture coords

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This commit is contained in:
Hajime Hoshi 2013-06-22 22:57:31 +09:00
parent 532528037a
commit 04ecb15be2
1 changed files with 26 additions and 20 deletions
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46
graphics/opengl/graphics_context.go
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@ -70,12 +70,14 @@ func (context *GraphicsContext) Fill(clr color.Color) {
func (context *GraphicsContext) DrawRect(rect graphics.Rect, clr color.Color) {
width := float32(context.currentOffscreenWidth)
height := float32(context.currentOffscreenHeight)
textureWidth := float32(Clp2(uint64(width)))
textureHeight := float32(Clp2(uint64(height)))
// Normalize the coord between -1.0 and 1.0.
x1 := float32(rect.X)/width*2.0 - 1.0
x2 := float32(rect.X+rect.Width)/width*2.0 - 1.0
y1 := float32(rect.Y)/height*2.0 - 1.0
y2 := float32(rect.Y+rect.Height)/height*2.0 - 1.0
x1 := float32(rect.X)/textureWidth*2.0 - 1.0
x2 := float32(rect.X+rect.Width)/textureHeight*2.0 - 1.0
y1 := float32(rect.Y)/textureHeight*2.0 - 1.0
y2 := float32(rect.Y+rect.Height)/textureHeight*2.0 - 1.0
vertex := [...]float32{
x1, y1,
x2, y1,
@ -196,6 +198,11 @@ func (context *GraphicsContext) SetOffscreen(textureID graphics.TextureID) {
func (context *GraphicsContext) setOffscreenFramebuffer(framebuffer C.GLuint,
textureWidth, textureHeight int) {
if framebuffer == context.mainFramebuffer {
textureWidth = int(Clp2(uint64(context.screenWidth * context.screenScale)))
textureHeight = int(Clp2(uint64(context.screenHeight * context.screenScale)))
}
C.glFlush()
C.glBindFramebuffer(C.GL_FRAMEBUFFER, framebuffer)
@ -205,23 +212,22 @@ func (context *GraphicsContext) setOffscreenFramebuffer(framebuffer C.GLuint,
C.glEnable(C.GL_BLEND)
C.glBlendFunc(C.GL_SRC_ALPHA, C.GL_ONE_MINUS_SRC_ALPHA)
width, height, tx, ty := 0, 0, 0, 0
C.glViewport(0, 0, C.GLsizei(abs(textureWidth)), C.GLsizei(abs(textureHeight)))
var e11, e22, e41, e42 float32
if framebuffer != context.mainFramebuffer {
width = textureWidth
height = textureHeight
tx = -1
ty = -1
e11 = float32(2) / float32(textureWidth)
e22 = float32(2) / float32(textureWidth)
e41 = -1
e42 = -1
} else {
width = context.screenWidth * context.screenScale
height = -1 * context.screenHeight * context.screenScale
tx = -1
ty = 1
height := float32(context.screenHeight) * float32(context.screenScale)
e11 = float32(2) / float32(textureWidth)
e22 = -1 * float32(2) / float32(textureHeight)
e41 = -1
e42 = -1 + height / float32(textureHeight) * 2
}
C.glViewport(0, 0, C.GLsizei(abs(width)), C.GLsizei(abs(height)))
e11 := float32(2.0) / float32(width)
e22 := float32(2.0) / float32(height)
e41 := float32(tx)
e42 := float32(ty)
context.projectionMatrix = [...]float32{
e11, 0, 0, 0,
0, e22, 0, 0,
@ -232,8 +238,8 @@ func (context *GraphicsContext) setOffscreenFramebuffer(framebuffer C.GLuint,
func (context *GraphicsContext) resetOffscreen() {
context.setOffscreenFramebuffer(context.mainFramebuffer, 0, 0)
context.currentOffscreenWidth = context.screenWidth
context.currentOffscreenHeight = context.screenHeight
context.currentOffscreenWidth = context.screenWidth * context.screenScale
context.currentOffscreenHeight = context.screenHeight * context.screenScale
}
// This method should be called on the UI thread.