GLSL-如何避免多边形重叠

Question

我正在GLSL中制作一个每像素的照明着色器。图中是一个立方体网格，根据绘制顺序，应该遮挡的边被渲染在其他边的顶部。当我切换到固定功能的opengl照明设置时，这不是问题。是什么原因导致的，我该如何修复？

它看起来像

顶点着色器：

varying vec4 ecPos;
varying vec3 normal;
void main()
{ 
gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
/* first transform the normal into eye space and normalize the result */
normal = normalize(gl_NormalMatrix * gl_Normal);
/* compute the vertex position  in camera space. */
ecPos = gl_ModelViewMatrix * gl_Vertex;

gl_Position = ftransform();
} 

片段着色器：

varying vec4 ecPos;
varying vec3 normal;
uniform sampler2D tex;
uniform vec2 resolution;
void main()
{
vec3 n,halfV,lightDir;
float NdotL,NdotHV;
vec4 color = gl_LightModel.ambient;
vec4 texC =  texture2D(tex,gl_TexCoord[0].st) * gl_LightSource[0].diffuse;
float att, dist;
/* a fragment shader can't write a verying variable, hence we need
a new variable to store the normalized interpolated normal */
n = normalize(normal);
// Compute the ligt direction
lightDir = vec3(gl_LightSource[0].position-ecPos);
/* compute the distance to the light source to a varying variable*/
dist = length(lightDir);

/* compute the dot product between normal and ldir */
NdotL = max(dot(n,normalize(lightDir)),0.0);
if (NdotL > 0.0) {
    att = 1.0 / (gl_LightSource[0].constantAttenuation +
            gl_LightSource[0].linearAttenuation * dist +
            gl_LightSource[0].quadraticAttenuation * dist * dist);
    color += att * (texC * NdotL + gl_LightSource[0].ambient);

    halfV = normalize(gl_LightSource[0].halfVector.xyz);
    NdotHV = max(dot(n,halfV),0.0);
    color += att * gl_FrontMaterial.specular * gl_LightSource[0].specular *   pow(NdotHV,gl_FrontMaterial.shininess); 
}

gl_FragColor = color;
}

着色器大多是这些着色器的修改版本http://www.lighthouse3d.com/tutorials/glsl-tutorial/point-light-per-pixel/

Answer 1

您可能忘记启用GL_DEPTH_TEST了。

您需要调用glEnable(GL_DEPTH_TEST);来启用OpenGL，以测试不同图元的深度。因此，当OpenGL进行渲染时，它不会在其他实际需要在后面的东西之上随机渲染东西！

http://www.opengl.org/sdk/docs/man/xhtml/glEnable.xml