iPhone-OpenGL ES 1.1-Alpha Blend使纹理颜色错误 [英] iPhone - OpenGL ES 1.1 - Alpha Blend make texture wrong color
问题描述
我是适用于iPhone的OpenGL ES 1.1的新手.今天,我尝试在黑色背景上绘制png纹理(该纹理包括alpha chanel),但结果与源png文件有所不同.
I'm newbie in OpenGL ES 1.1 for iPhone. Today, I tried to draw png texture on black background (the texture includes the alpha chanel) but the result is diference from source png file.
iPhone上的结果模拟器:
The Result on iPhone & Simulator:
关闭灯:
应该是(更亮和更模糊):
It's should be (Brighter & more blur):
源纹理文件:
这是我使用的源代码:
//Setup:
glEnable(GL_ALPHA_TEST);
glEnable(GL_BLEND);
glAlphaFunc(GL_GREATER,0.01);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
static const GLfloat light0Ambient[] = {1.0, 1.0, 1.0, 1.0};
static const GLfloat light0Diffuse[] = {1.0, 1.0, 1.0, 1.0};
static const GLfloat light0Position[] = {0.0, 0.0, 10.0};
glLightfv(GL_LIGHT0, GL_AMBIENT, (const GLfloat *)light0Ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, (const GLfloat *)light0Diffuse);
glLightfv(GL_LIGHT0, GL_POSITION, (const GLfloat *)light0Position);
glEnable(GL_TEXTURE_2D);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glEnableClientState(GL_NORMAL_ARRAY);
绘图代码:
glBindTexture(GL_TEXTURE_2D, OYTextID);
glVertexPointer(3, GL_FLOAT, 0, GUI_Vertices);
glNormalPointer(GL_FLOAT, 0, GUI_Normals);
glTexCoordPointer(2, GL_FLOAT, 0, GUI_TexCoords);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
是什么原因导致颜色出错?
What is the issue make the color goes wrong ??
感谢您的阅读,非常感谢您的帮助. 最好的问候和对不起,我的英语.
Thanks for reading, I appreciate any help. Best Regard & sorry for my English.
推荐答案
好像您的PNG文件已经预乘alpha.在这种情况下,您需要设置
Looks like your PNG file has already premultiplied alpha. In this case you need to set
glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA); // GL_ONE instead of GL_SRC_ALPHA
这篇关于iPhone-OpenGL ES 1.1-Alpha Blend使纹理颜色错误的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!