如何解决将Orange Book着色器移植到OpenGL ES 2.0
| 我正在尝试将Orange Book砖着色器移植到OpenGL ES 2.0,但是我遇到了照明问题。在没有照明的情况下,我看到的是砖块,但砖块的形状只是黑色。 垂直const float ZERO = 0.0;
const float ONE = 1.0;
// Should be built in,but this is GLES
uniform mat4 ModelViewMatrix;
uniform mat4 ModelViewProjectionMatrix;
uniform mat3 NormalMatrix;
attribute vec4 Vertex;
attribute vec3 Normal;
// Other variables
uniform vec3 LightPosition;
const float SpecularContribution = 0.3;
const float DiffuseContribution = 1.0 - SpecularContribution;
varying float LightIntensity;
varying vec2 MCPosition;
void main()
{
vec3 ecPosition = vec3(ModelViewMatrix * Vertex);
vec3 tnorm = normalize(NormalMatrix * Normal);
vec3 lightVec = normalize(LightPosition - ecPosition);
vec3 reflectVec = reflect(-lightVec,tnorm);
vec3 viewVec = normalize(-ecPosition);
float diffuse = max(dot(lightVec,tnorm),ZERO);
float spec = ZERO;
if(diffuse > ZERO)
{
spec = max(dot(reflectVec,viewVec),ZERO);
spec = pow(spec,16.0);
}
LightIntensity = DiffuseContribution * diffuse +
SpecularContribution * spec;
MCPosition = Vertex.xy;
gl_Position = ModelViewProjectionMatrix * Vertex;
}
易碎
precision mediump float;
const float ONE = 1.0;
const float HALF = 0.5;
uniform vec3 BrickColor,MortarColor;
uniform vec2 BrickSize,BrickPercent;
varying float LightIntensity;
varying vec2 MCPosition;
void main()
{
vec3 color;
vec2 position,useBrick;
position = MCPosition / BrickSize;
if(fract(position.y * HALF) > HALF)
position.x += HALF;
position = fract(position);
useBrick = step(position,BrickPercent);
color = mix(MortarColor,BrickColor,useBrick.x * useBrick.y);
color *= LightIntensity;
gl_FragColor = vec4(color,ONE);
}
这是我的Java
@Override
public void onSurfaceCreated(GL10 glUnused,EGLConfig config)
{
GLES20.glClearColor(0.3922f,0.5843f,0.9294f,1.0f);
GLES20.glEnable(GLES20.GL_DEPTH_TEST);
try
{
mTorus.genTorus(60,1.25f,0.5f);
mAngle = 45.0f;
mProgramObject = ESShader.loadProgram(mContext,\"cube.vert\",\"cube.frag\");
mModelViewLoc = GLES20.glGetUniformLocation(mProgramObject,\"ModelViewMatrix\");
mMVPLoc = GLES20.glGetUniformLocation(mProgramObject,\"ModelViewProjectionMatrix\");
mNormalMatrixLoc = GLES20.glGetUniformLocation(mProgramObject,\"NormalMatrix\");
mLightPositionLoc = GLES20.glGetUniformLocation(mProgramObject,\"LightPosition\");
mBrickColorLoc = GLES20.glGetUniformLocation(mProgramObject,\"BrickColor\");
mMortarColorLoc = GLES20.glGetUniformLocation(mProgramObject,\"MortarColor\");
mBrickSizeLoc = GLES20.glGetUniformLocation(mProgramObject,\"BrickSize\");
mBrickPercentLoc = GLES20.glGetUniformLocation(mProgramObject,\"BrickPercent\");
mPositionLoc = GLES20.glGetAttribLocation(mProgramObject,\"Vertex\");
mNormalLoc = GLES20.glGetAttribLocation(mProgramObject,\"Normal\");
}
catch(IOException ioe)
{
System.err.println(\"Failed to load shaders\");
}
}
@Override
public void onSurfaceChanged(GL10 glUnused,int width,int height)
{
mWidth = width;
mHeight = height;
mProjection.loadIdentity();
mProjection.perspective(60.0f,(float)mWidth / (float)mHeight,1.0f,20.0f);
GLES20.glViewport(0,mWidth,mHeight);
}
private void update()
{
if(mLastTime == 0) mLastTime = SystemClock.uptimeMillis();
long curTime = SystemClock.uptimeMillis();
long elapsedTime = curTime - mLastTime;
float deltaTime = elapsedTime / 1000.0f;
mLastTime = curTime;
// Compute a rotation angle based on time to rotate the cube
mAngle += (deltaTime * 40.0f);
if(mAngle >= 360.0f) mAngle -= 360.0f;
}
@Override
public void onDrawFrame(GL10 glUnused)
{
update();
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
// Use the program object
GLES20.glUseProgram(mProgramObject);
mModelView.loadIdentity();
mModelView.translate(0.0f,0.0f,-5.0f);
mModelView.rotate(mAngle,0.75f);
mNormalMatrix.load(mModelView);
mNormalMatrix.invert();
mNormalMatrix.transpose();
mMVPMatrix.multiply(mModelView,mProjection);
GLES20.glUniformMatrix4fv(mModelViewLoc,1,false,mModelView.getAsFloatBuffer());
GLES20.glUniformMatrix4fv(mMVPLoc,mMVPMatrix.getAsFloatBuffer());
GLES20.glUniformMatrix4fv(mNormalMatrixLoc,mNormalMatrix.getAsFloatBuffer());
GLES20.glUniform3f(mLightPositionLoc,5.0f,5.0f);
GLES20.glUniform3f(mBrickColorLoc,0.549f,0.239f,0.271f);
GLES20.glUniform3f(mMortarColorLoc,0.8f,0.8f);
GLES20.glUniform2f(mBrickSizeLoc,0.3f,0.15f);
GLES20.glUniform2f(mBrickPercentLoc,0.9f,0.85f);
GLES20.glVertexAttribPointer(mPositionLoc,3,GLES20.GL_FLOAT,mTorus.getVertices());
GLES20.glEnableVertexAttribArray(mPositionLoc);
GLES20.glVertexAttribPointer(mNormalLoc,mTorus.getNormals());
GLES20.glEnableVertexAttribArray(mNormalLoc);
GLES20.glDrawElements(GLES20.GL_TRIANGLES,mTorus.getNumIndices(),GLES20.GL_UNSIGNED_SHORT,mTorus.getIndices());
}
解决方法
问题是我为NormalMatrix传递了错误的值。 NormalMatrix是ModelViewMatrix逆矩阵的转置的左上3x3。为此,我有以下代码:
mNormalMatrix.load(mModelView);
mNormalMatrix.invert();
mNormalMatrix.transpose();
这产生了一个4x4矩阵,但是在我的着色器中,我将其作为mat3,这改变了值并使其失败。
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