我正在尝试纹理贴图一些四边形。我可以用纯色渲染四边形就好了。我一直在关注这个页面： http: //www.learnopengles.com/android-lesson-four-introducing-basic-texturing/
一切都编译并运行，但纹理根本没有被应用。我的代码和链接的页面之间的唯一区别是我不执行 glBindAttribLocation，并且我使用 glDrawElements 而不是 glDrawArrays。
编辑：将我的顶点和 tex 坐标数据转换为使用 glDrawArrays 并没有解决任何问题。
我所有的着色器句柄似乎都是正确的。问题一定出在我的一张画上。如果有人可以帮我调试这个，那就太好了。我尝试设置 gl_FragColor = vec4(texCoord[0], texCoord[1], 1.0f, 1.0f) 只是为了查看 tex 坐标是否正在进入着色器，但是会崩溃。
顶点数据的初始化：
static float squareCoords[] = { -0.5f, 0.5f, 0.0f, // top left
-0.5f, -0.5f, 0.0f, // bottom left
0.5f, -0.5f, 0.0f, // bottom right
0.5f, 0.5f, 0.0f }; // top right
static float textureCoords[] = { 0.0f, 1.0f, // top left
0.0f, 0.0f, // bottom left
1.0f, 0.0f, // bottom right
1.0f, 1.0f}; // top right
// initialize vertex byte buffer for shape coordinates
ByteBuffer bb = ByteBuffer.allocateDirect(squareCoords.length * 4); // (# of coordinate values * 4 bytes per float)
bb.order(ByteOrder.nativeOrder());
vertexBuffer = bb.asFloatBuffer();
vertexBuffer.put(squareCoords);
vertexBuffer.position(0);
ByteBuffer tcbb = ByteBuffer.allocateDirect(textureCoords.length * 4);
tcbb.order(ByteOrder.nativeOrder());
texCoordBuffer = tcbb.asFloatBuffer();
texCoordBuffer.put(textureCoords);
texCoordBuffer.position(0);
// initialize byte buffer for the draw list
ByteBuffer dlb = ByteBuffer.allocateDirect(
// (# of coordinate values * 2 bytes per short)
drawOrder.length * 2);
dlb.order(ByteOrder.nativeOrder());
drawListBuffer = dlb.asShortBuffer();
drawListBuffer.put(drawOrder);
drawListBuffer.position(0);
在我的附加着色器代码中：
// get handle to texture coords
mTexCoordHandle = GLES20.glGetAttribLocation(mProgram, "texCoord");
MyGLRenderer.checkGlError("glGetAttribLocation");
Log.i("TEXCOORD SHADER HANDLE", " " + mTexCoordHandle);
//get handle to texture
mTexHandle = GLES20.glGetUniformLocation(mProgram, "u_texture");
MyGLRenderer.checkGlError("glGetUniformLocation");
Log.i("TEX SHADER HANDLE", " " + mTexHandle);
在我的主要（粒子引擎）绘图中：
// Enable a handle to the triangle vertices
GLES20.glEnableVertexAttribArray(mPositionHandle);
// Prepare the triangle coordinate data
GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
GLES20.GL_FLOAT, false,
0, vertexBuffer);
GLES20.glEnableVertexAttribArray(mTexCoordHandle);
GLES20.glVertexAttribPointer(mTexCoordHandle, TEX_COORDS_PER_VERTEX,
GLES20.GL_FLOAT, false,
0, texCoordBuffer);
// Set the active texture unit to texture unit 0.
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
// Bind the texture to this unit.
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureDataHandle);
// Tell the texture uniform sampler to use this texture in the shader by binding to texture unit 0.
GLES20.glUniform1i(mTexHandle, 0);
for (int t=0;t<mChildsCount;t++) {
Particle child = (Particle)mChilds[t];
child.draw(mVMatrix, mProjMatrix);
}
// Disable vertex array
GLES20.glDisableVertexAttribArray(mPositionHandle);
GLES20.glDisableVertexAttribArray(mTexCoordHandle);
在单个粒子中绘制：
//... calculate model-view-projection matrix, send to shader
GLES20.glDrawElements(GLES20.GL_TRIANGLES, mPEngine.drawOrder.length,
GLES20.GL_UNSIGNED_SHORT, mPEngine.drawListBuffer);
在我的加载纹理中：
public static int loadTexture(final Context context, final int resourceId)
{
final int[] textureHandle = new int[1];
GLES20.glGenTextures(1, textureHandle, 0);
if (textureHandle[0] != 0)
{
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inScaled = false; // No pre-scaling
// Read in the resource
final Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), resourceId, options);
if (bitmap == null) {
throw new RuntimeException("Error decoding bitmap");
}
// Bind to the texture in OpenGL
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureHandle[0]);
// Set filtering
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST);
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST);
// Load the bitmap into the bound texture.
GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0);
// Recycle the bitmap, since its data has been loaded into OpenGL.
bitmap.recycle();
}
if (textureHandle[0] == 0)
{
throw new RuntimeException("Error loading texture.");
}
return textureHandle[0];
}
在我的着色器中：
private final String vertexShaderCode =
// This matrix member variable provides a hook to manipulate
// the coordinates of the objects that use this vertex shader
"uniform mat4 uMVPMatrix;" +
"attribute vec4 vPosition;" +
"attribute vec2 texCoord;" +
"varying vec2 texCoordOut;" +
"void main() {" +
// the matrix must be included as a modifier of gl_Position
" texCoordOut = texCoord; \n" +
" gl_Position = uMVPMatrix * vPosition; \n" +
"}";
private final String fragmentShaderCode =
"precision mediump float;" +
"varying vec2 texCoordOut;" +
"uniform sampler2D u_texture;" +
"void main() {" +
" vec4 texColor = texture2D(u_texture, texCoordOut);\n" +
" gl_FragColor = texColor;" +
"}";