我正在編寫一個在iOS上使用OpenGL ES 1.1中的點精靈的粒子系統。一切都很好,直到我嘗試紋理點精靈爲止......當我渲染時,每個精靈都被我加載的紋理的左上角像素着色(而不是顯示圖像)。我試過不同的圖像和不同的尺寸,並始終得到相同的結果。如何在OpenGL ES 1.1中指定點精靈紋理座標?
設置代碼(從GLPaint例如拍攝):
CGImageRef brushImage;
CGContextRef brushContext;
size_t width, height;
GLubyte *brushData;
brushImage = [UIImage imageNamed:@"Particle.png"].CGImage;
width = CGImageGetWidth(brushImage);
height = CGImageGetHeight(brushImage);
if(brushImage) {
brushData = (GLubyte *) calloc(width * height * 4, sizeof(GLubyte));
brushContext = CGBitmapContextCreate(brushData, width, width, 8, width * 4, CGImageGetColorSpace(brushImage), kCGImageAlphaPremultipliedLast);
CGContextDrawImage(brushContext, CGRectMake(0, 0.0, (CGFloat)width, (CGFloat)height), brushImage);
CGContextRelease(brushContext);
glGenTextures(1, &brushTexture);
glBindTexture(GL_TEXTURE_2D, brushTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, brushData);
free(brushData);
}
和渲染代碼:
glLoadIdentity();
glEnable(GL_BLEND);
glTranslatef(0.0f,0.0f,0.0f);
glClearColor(0.0, 0.0, 0.0, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glEnableClientState(GL_POINT_SPRITE_OES);
glEnableClientState(GL_POINT_SIZE_ARRAY_OES);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, brushTexture);
glTexEnvf(GL_POINT_SPRITE_OES, GL_COORD_REPLACE_OES, GL_TRUE);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
// took this out as incorrect call glEnableClientState(GL_POINT_SMOOTH);
glVertexPointer(2, GL_FLOAT, sizeof(ColoredVertexData2D), &vertexData[0].vertex);
glColorPointer(4, GL_FLOAT, sizeof(ColoredVertexData2D), &vertexData[0].color);
glPointSizePointerOES(GL_FLOAT,sizeof(ColoredVertexData2D),&vertexData[0].size)
glDrawArrays(GL_POINTS, 0,1000);
當紋理點精靈,你必須指定紋理座標,如果是這樣,怎麼樣?
我認爲GL_POINT_SMOOTH與點精靈不兼容,但它不是客戶端狀態標誌。至少值得去掉那條線! – 2010-11-14 23:58:30
這實際上是一個巨大的幫助:當我將該行更改爲glEnable(GL_POINT_SMOOTH)時,我得到彩色圓圈而不是彩色方塊...完全刪除它沒有任何影響:我可以只渲染點而不是點精靈嗎? – joshue 2010-11-15 00:36:28