我正在尝试使用OpenGL ES 2.0在每张脸上绘制一个具有不同颜色的立方体。我现在只能用一种颜色画一个立方体。我知道在这种情况下我需要使用VertexAttribPointer而不是Uniform，但我可能错误地添加了它们。我实现代码后屏幕显示没有。这是我的代码，任何人都可以帮忙吗？非常感谢你!!!
public class MyCube {
private FloatBuffer vertexBuffer;
private ShortBuffer drawListBuffer;
private ShortBuffer[] ArrayDrawListBuffer;
private FloatBuffer colorBuffer;
private int mProgram;
//For Projection and Camera Transformations
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;" +
"void main() {" +
// the matrix must be included as a modifier of gl_Position
// Note that the uMVPMatrix factor *must be first* in order
// for the matrix multiplication product to be correct.
" gl_Position = uMVPMatrix * vPosition;" +
"}";
// Use to access and set the view transformation
private int mMVPMatrixHandle;
private final String fragmentShaderCode =
"precision mediump float;" +
"uniform vec4 vColor;" +
"void main() {" +
" gl_FragColor = vColor;" +
"}";
// number of coordinates per vertex in this array
static final int COORDS_PER_VERTEX = 3;
float cubeCoords[] = {
-0.5f, 0.5f, 0.5f, // front top left 0
-0.5f, -0.5f, 0.5f, // front bottom left 1
0.5f, -0.5f, 0.5f, // front bottom right 2
0.5f, 0.5f, 0.5f, // front top right 3
-0.5f, 0.5f, -0.5f, // back top left 4
0.5f, 0.5f, -0.5f, // back top right 5
-0.5f, -0.5f, -0.5f, // back bottom left 6
0.5f, -0.5f, -0.5f, // back bottom right 7
};
// Set color with red, green, blue and alpha (opacity) values
float color[] = { 0.63671875f, 0.76953125f, 0.22265625f, 1.0f };
float red[] = { 1.0f, 0.0f, 0.0f, 1.0f };
float blue[] = { 0.0f, 0.0f, 1.0f, 1.0f };
private short drawOrder[] = {
0, 1, 2, 0, 2, 3,//front
0, 4, 5, 0, 5, 3, //Top
0, 1, 6, 0, 6, 4, //left
3, 2, 7, 3, 7 ,5, //right
1, 2, 7, 1, 7, 6, //bottom
4, 6, 7, 4, 7, 5};//back (order to draw vertices)
final float[] cubeColor =
{
// Front face (red)
1.0f, 0.0f, 0.0f, 1.0f,
1.0f, 0.0f, 0.0f, 1.0f,
1.0f, 0.0f, 0.0f, 1.0f,
1.0f, 0.0f, 0.0f, 1.0f,
1.0f, 0.0f, 0.0f, 1.0f,
1.0f, 0.0f, 0.0f, 1.0f,
// Top face (green)
0.0f, 1.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f, 1.0f,
// Left face (blue)
0.0f, 0.0f, 1.0f, 1.0f,
0.0f, 0.0f, 1.0f, 1.0f,
0.0f, 0.0f, 1.0f, 1.0f,
0.0f, 0.0f, 1.0f, 1.0f,
0.0f, 0.0f, 1.0f, 1.0f,
0.0f, 0.0f, 1.0f, 1.0f,
// Right face (yellow)
1.0f, 1.0f, 0.0f, 1.0f,
1.0f, 1.0f, 0.0f, 1.0f,
1.0f, 1.0f, 0.0f, 1.0f,
1.0f, 1.0f, 0.0f, 1.0f,
1.0f, 1.0f, 0.0f, 1.0f,
1.0f, 1.0f, 0.0f, 1.0f,
// Bottom face (cyan)
0.0f, 1.0f, 1.0f, 1.0f,
0.0f, 1.0f, 1.0f, 1.0f,
0.0f, 1.0f, 1.0f, 1.0f,
0.0f, 1.0f, 1.0f, 1.0f,
0.0f, 1.0f, 1.0f, 1.0f,
0.0f, 1.0f, 1.0f, 1.0f,
// Back face (magenta)
1.0f, 0.0f, 1.0f, 1.0f,
1.0f, 0.0f, 1.0f, 1.0f,
1.0f, 0.0f, 1.0f, 1.0f,
1.0f, 0.0f, 1.0f, 1.0f,
1.0f, 0.0f, 1.0f, 1.0f,
1.0f, 0.0f, 1.0f, 1.0f
};
public MyCube() {
// initialize vertex byte buffer for shape coordinates
ByteBuffer bb = ByteBuffer.allocateDirect(
// (# of coordinate values * 4 bytes per float)
cubeCoords.length * 4);
bb.order(ByteOrder.nativeOrder());
vertexBuffer = bb.asFloatBuffer();
vertexBuffer.put(cubeCoords);
vertexBuffer.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);
// initialize byte buffer for the color list
ByteBuffer cb = ByteBuffer.allocateDirect(
// (# of coordinate values * 2 bytes per short)
cubeColor.length * 4);
cb.order(ByteOrder.nativeOrder());
colorBuffer = cb.asFloatBuffer();
colorBuffer.put(cubeColor);
colorBuffer.position(0);
int vertexShader = MyRenderer.loadShader(GLES20.GL_VERTEX_SHADER,
vertexShaderCode);
int fragmentShader = MyRenderer.loadShader(GLES20.GL_FRAGMENT_SHADER,
fragmentShaderCode);
// create empty OpenGL ES Program
mProgram = GLES20.glCreateProgram();
// add the vertex shader to program
GLES20.glAttachShader(mProgram, vertexShader);
// add the fragment shader to program
GLES20.glAttachShader(mProgram, fragmentShader);
// creates OpenGL ES program executables
GLES20.glLinkProgram(mProgram);
}
private int mPositionHandle;
private int mColorHandle;
private final int vertexCount = cubeCoords.length / COORDS_PER_VERTEX;
private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex
public void draw(float[] mvpMatrix) { // pass in the calculated transformation matrix
// Add program to OpenGL ES environment
GLES20.glUseProgram(mProgram);
// get handle to vertex shader's vPosition member
mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
// get handle to fragment shader's vColor member
mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
// Enable a handle to the cube vertices
GLES20.glEnableVertexAttribArray(mPositionHandle);
// Prepare the cube coordinate data
GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
GLES20.GL_FLOAT, false,
vertexStride, vertexBuffer);
// Set color for drawing the triangle
//mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
// Enable a handle to the cube colors
GLES20.glEnableVertexAttribArray(mColorHandle);
// Prepare the cube color data
GLES20.glVertexAttribPointer(mColorHandle, 4, GLES20.GL_FLOAT, false, 16, colorBuffer);
// Set the color for each of the faces
//GLES20.glUniform4fv(mColorHandle, 1, blue, 0);
//***When I add this line of code above, it can show a cube totally in blue.***
// get handle to shape's transformation matrix
mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
// Pass the projection and view transformation to the shader
GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0);
// Draw the cube
GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length, GLES20.GL_UNSIGNED_SHORT, drawListBuffer);
// Disable vertex array
GLES20.glDisableVertexAttribArray(mPositionHandle);
GLES20.glDisableVertexAttribArray(mColorHandle);
GLES20.glDisableVertexAttribArray(mMVPMatrixHandle);
}
}
答案 0 :(得分：1)
从片段着色器中删除统一变量vColor声明。在顶点着色器中定义新的每顶点属性输入变量，将该值写入由顶点着色器输出的变量变量，并添加为由片段着色器读取的变化输入。