2017-12-27 210 views
1

我有行,我想用数组的颜色绘制它们。OpenGL ES 3.0 Java使用颜色Array绘制顶点(每个顶点颜色不同)

颜色数组是一个FloatBuffer,每个顶点都有RGBA数据。

我尝试了这种方式,但它不工作:

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;" + 
    "}"; 

的绘图方法:

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); 
} 

我用2个坐标设置顶点(COORDS_PER_VERTEX = 2)。

什么问题?

回答

1

glEnableClientStateglColorPointer不是OpenGL ES的一部分。它们是Legacy OpenGL的一部分,并且已弃用Fixed Function Pipeline

如果您使用统一的变量的颜色,那么整条生产线成为被设置为统一的可变颜色的彩色:

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,如果你要定义不同的颜色属性为每个顶点属性,那么你必须声明一个颜色属性,就像你为顶点坐标所做的那样。你必须从顶点着色器的属性传递给片段着色器:

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;" + 
    "}"; 

定义颜色属性,你与顶点做到这一点坐标属性:

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);