我正在尝试将Orange Book砖块着色器移植到OpenGL ES 2.0,我遇到了照明问题。在灯光下,我看到了砖块,但是它的形状只是黑色。
Vert的
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;
}
分片
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, 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, 1.0f, 0.0f, 0.75f);
mNormalMatrix.load(mModelView);
mNormalMatrix.invert();
mNormalMatrix.transpose();
mMVPMatrix.multiply(mModelView, mProjection);
GLES20.glUniformMatrix4fv(mModelViewLoc, 1, false, mModelView.getAsFloatBuffer());
GLES20.glUniformMatrix4fv(mMVPLoc, 1, false, mMVPMatrix.getAsFloatBuffer());
GLES20.glUniformMatrix4fv(mNormalMatrixLoc, 1, false, mNormalMatrix.getAsFloatBuffer());
GLES20.glUniform3f(mLightPositionLoc, 5.0f, 5.0f, 5.0f);
GLES20.glUniform3f(mBrickColorLoc, 0.549f, 0.239f, 0.271f);
GLES20.glUniform3f(mMortarColorLoc, 0.8f, 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, false, 0, mTorus.getVertices());
GLES20.glEnableVertexAttribArray(mPositionLoc);
GLES20.glVertexAttribPointer(mNormalLoc, 3, GLES20.GL_FLOAT, false, 0, mTorus.getNormals());
GLES20.glEnableVertexAttribArray(mNormalLoc);
GLES20.glDrawElements(GLES20.GL_TRIANGLES, mTorus.getNumIndices(), GLES20.GL_UNSIGNED_SHORT, mTorus.getIndices());
}
答案 0 :(得分:3)
问题在于我为NormalMatrix传递了错误的值。 NormalMatrix是ModelViewMatrix反转的Transpose的左上3x3。为此,我有这个代码:
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把它作为mat3,这会使值移动并使其失败。