我有线条,我想用数组的颜色绘制它们。
颜色数组是一个FloatBuffer,每个顶点都有RGBA数据。
我试过这种方式,但它不起作用:
着色器代码:
private final String vertexShaderCode =
"uniform mat4 uMVPMatrix;" +
"attribute vec4 vPosition;" +
"void main() {" +
" gl_Position = vPosition;" +
"}";
private final String fragmentShaderCode =
"precision mediump float;" +
"uniform vec4 vColor;" +
"void main() {" +
" gl_FragColor = vColor;" +
"}";
绘图方法:
public void draw(GL10 gl)
{
GLES30.glUseProgram(mProgram);
mPositionHandle = GLES30.glGetAttribLocation(mProgram, "vPosition");
GLES30.glEnableVertexAttribArray(mPositionHandle);
GLES30.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES30.GL_FLOAT, false, vertexStride, vertexBuffer);
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
gl.glColorPointer(vertexBufferSize / 4 / 4, GL10.GL_FLOAT, 4*4, colorBuffer);
GLES30.glDrawArrays(GLES30.GL_LINES, 0, vertexBufferSize / 4 / COORDS_PER_VERTEX);
GLES30.glDisableVertexAttribArray(mPositionHandle);
gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
}
我使用2个坐标来设置顶点(COORDS_PER_VERTEX = 2)。
有什么问题?
答案 0 :(得分:1)
glEnableClientState
和glColorPointer
不属于OpenGL ES。它们是Legacy OpenGL的一部分,已弃用Fixed Function Pipeline。
如果对颜色使用统一变量,则整条线将以设置为均匀变量的颜色着色:
int color_loc = GLES30.glGetUniformLocation(mProgram, "vColor")
GLES30.glUseProgram(mProgram);
GLES30.glUniform4f(color_loc, 1.0, 0.0, 0.0, 1.0); // red
mPositionHandle = GLES30.glGetAttribLocation(mProgram, "vPosition");
GLES30.glEnableVertexAttribArray(mPositionHandle);
GLES30.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES30.GL_FLOAT, false, vertexStride, vertexBuffer);
GLES30.glDrawArrays(GLES30.GL_LINES, 0, vertexBufferSize / 4 / COORDS_PER_VERTEX);
GLES30.glDisableVertexAttribArray(mPositionHandle);
但是,如果要为每个顶点属性定义不同的颜色属性,则必须声明颜色属性,类似于对顶点坐标执行的操作。您必须将属性从顶点着色器传递到片段着色器:
private final String vertexShaderCode =
"uniform mat4 uMVPMatrix;" +
"attribute vec4 aPosition;" +
"attribute vec4 aColor;" +
"varying vec4 vColor;" +
"void main() {" +
" vColor = aColor;" +
" gl_Position = aPosition;" +
"}";
private final String fragmentShaderCode =
"precision mediump float;" +
"varying vec4 vColor;" +
"void main() {" +
" gl_FragColor = vColor;" +
"}";
使用顶点坐标属性定义颜色属性:
mPositionHandle = GLES30.glGetAttribLocation(mProgram, "aPosition");
mColorHandle = GLES30.glGetAttribLocation(mProgram, "aColor");
GLES30.glEnableVertexAttribArray(mPositionHandle);
GLES30.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES30.GL_FLOAT, false, vertexStride, vertexBuffer);
GLES30.glEnableVertexAttribArray(mColorHandle);
GLES30.glVertexAttribPointer(mColorHandle, 4, GLES30.GL_FLOAT, false, 0, colorBuffer);
GLES30.glDrawArrays(GLES30.GL_LINES, 0, vertexBufferSize / 4 / COORDS_PER_VERTEX);
GLES30.glDisableVertexAttribArray(mPositionHandle);
GLES30.glDisableVertexAttribArray(mColorHandle);