Shader language 自西向东旋转的地球_shader 球上下旋转-优快云博客

本文介绍了一种使用AMDRenderMonkey进行调试的方法。该方法通过VertexProgram和FragmentProgram两个部分实现，VertexProgram负责顶点处理，其中包括了坐标转换、角度计算等步骤；FragmentProgram则主要处理纹理映射。

可以使用AMD Render Monkey 调试

Vertex Program:

uniform float cos_time_0_2PI, sin_time_0_2PI, time0_1;
varying vec2 TexCoord;
varying float R,r,theta, phi;
varying vec4 pos;

const float PI = 3.141592653589793;

void main(void)
{
 TexCoord    = vec2 (gl_MultiTexCoord0);
 //TexCoord.x  = -TexCoord.x;
 //TexCoord.y  = -TexCoord.y;
 
 pos = gl_Vertex;
 R = sqrt(pos.x * pos.x + pos.y * pos.y + pos.z * pos.z);
 r = sqrt(R * R - pos.y * pos.y);
 theta = 2.0 * PI * time0_1 ;
 
 if(pos.x + 0.01 > r){
     phi = 0.0;
 }else if(pos.x - 0.01 < -r){
     phi = PI;
 }else{
     phi = acos(pos.x / r);
 }
 
 if(pos.z < 0.0){
     phi = 2.0 * PI - phi;
 }
 
 pos.x = r * cos(theta + phi);
 pos.z = r * sin(theta + phi);
 
 if(pos.y + 0.000001 > R){
     pos.y = R;
     r = 0.0;
     pos.x = 0.0;
     pos.z = 0.0;
 }else if(pos.y - 0.000001 < -R){
     pos.y = -R;
     r = 0.0;
     pos.x = 0.0;
     pos.z = 0.0;
 }
 
 gl_Position = gl_ModelViewProjectionMatrix * pos; 
}

Fragment Program:

uniform sampler2D myTexture;
varying vec2 TexCoord;
varying float R,r,theta;
varying vec4 pos;


void main (void)
{
  gl_FragColor  = texture2D(myTexture, TexCoord);        
  //gl_FragColor = vec4(1,0,0,1); 
}