GLSL中的纹理投影
我正在尝试直接基于这个示例实现纹理投影。我的环境是Android 2.2上的OpenGL ES 2.0 矩阵数学从来不是我的强项,我怀疑我的问题出在纹理投影矩阵设置(texGenMatrix)的某个地方。我已经尝试了一切可以想象的方法来让它工作,但是投影没有正确出来。如果能多看几眼我的代码,我将不胜感激。谢谢 此处未显示的是我的几何体(穿过原点的水平面),以及其他一些类似管道的着色器统一/属性绑定 摄像机设置:GLSL中的纹理投影,glsl,textures,projection,Glsl,Textures,Projection,我正在尝试直接基于这个示例实现纹理投影。我的环境是Android 2.2上的OpenGL ES 2.0 矩阵数学从来不是我的强项,我怀疑我的问题出在纹理投影矩阵设置(texGenMatrix)的某个地方。我已经尝试了一切可以想象的方法来让它工作,但是投影没有正确出来。如果能多看几眼我的代码,我将不胜感激。谢谢 此处未显示的是我的几何体(穿过原点的水平面),以及其他一些类似管道的着色器统一/属性绑定 摄像机设置: // Set the camera projection matrix Matri
// Set the camera projection matrix
Matrix.frustumM(cameraProjMatrix, 0,
-nearPlaneSize.x, nearPlaneSize.x, // near plane left/right
-nearPlaneSize.y, nearPlaneSize.y, // near plane bottom/top
nearPlaneDistance, farPlaneDistance // near/far plane distance
);
// Set the camera view matrix
Matrix.setLookAtM(cameraViewMatrix, 0,
0, 100, 100, // eye
0, 0, 0, // center
0, 1, 0 // up-vector
);
// Translate the model as needed
Matrix.translateM(modelMatrix, 0, x, y, z);
// Calculate the model * view matrix
Matrix.multiplyMM(modelViewMatrix, 0, cameraViewMatrix, 0, modelMatrix, 0);
// Calculate the inverse camera view matrix (needed in the vert shader)
Matrix.invertM(inverseCameraViewMatrix, 0, cameraViewMatrix, 0);
纹理投影设置:
// Set a texture projection matrix
Matrix.frustumM(texProjMatrix, 0,
-nearPlaneSize.x, nearPlaneSize.x, // near plane left/right
-nearPlaneSize.y, nearPlaneSize.y, // near plane bottom/top
nearPlaneDistance, farPlaneDistance // near/far plane distance
);
// Set the texture projection to point down at the origin
Matrix.setLookAtM(texViewMatrix, 0,
0, 100, 10, // eye
0, 0, 0, // center
0, 1, 0 // up-vector
);
// scale bias
float[] scaleBiasMatrix = new float[] { 0.5f, 0.0f, 0.0f, 0.0f,
0.0f, 0.5f, 0.0f, 0.0f,
0.0f, 0.0f, 0.5f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f
};
// calculate the TexGenMatrix
Matrix.multiplyMM(texGenMatrix, 0, scaleBiasMatrix, 0, texProjMatrix, 0);
Matrix.multiplyMM(texGenMatrix, 0, texGenMatrix, 0, texViewMatrix, 0);
顶点着色器:
attribute vec3 aPosition; // vertex x y z
uniform mat4 texGenMatrix;
uniform mat4 modelViewMatrix;
uniform mat4 cameraProjMatrix;
varying vec4 vProjCoord;
void main() {
gl_Position = cameraProjMatrix * modelViewMatrix * aPosition;
vec4 posEye = modelViewMatrix * aPosition;
vec4 posWorld = inverseCameraViewMatrix * posEye;
vProjCoord = texGenMatrix * posWorld;
}
uniform sampler2D projectionMap;
varying vec4 vProjCoord;
void main() {
vec3 finalColor = vec3( 0.5, 0.5, 0.5);
if (vProjCoord.q > 0.0) {
vec4 ProjMapColor = texture2DProj(projectionMap, vProjCoord);
finalColor += ProjMapColor.rgb;
}
gl_FragColor = vec4(finalColor, 1.0);
}
片段着色器:
attribute vec3 aPosition; // vertex x y z
uniform mat4 texGenMatrix;
uniform mat4 modelViewMatrix;
uniform mat4 cameraProjMatrix;
varying vec4 vProjCoord;
void main() {
gl_Position = cameraProjMatrix * modelViewMatrix * aPosition;
vec4 posEye = modelViewMatrix * aPosition;
vec4 posWorld = inverseCameraViewMatrix * posEye;
vProjCoord = texGenMatrix * posWorld;
}
uniform sampler2D projectionMap;
varying vec4 vProjCoord;
void main() {
vec3 finalColor = vec3( 0.5, 0.5, 0.5);
if (vProjCoord.q > 0.0) {
vec4 ProjMapColor = texture2DProj(projectionMap, vProjCoord);
finalColor += ProjMapColor.rgb;
}
gl_FragColor = vec4(finalColor, 1.0);
}
棘手的事情,不是吗?你设法让它工作了吗?我正在尝试在OpenGL C++中实现一些东西,如果你有工作样例代码,我会喜欢的!如果你能发布一个屏幕截图,展示的内容会更简单。(我知道这是一个有8年历史的帖子)。多亏了你的代码,我才能够实现纹理投影。