我可以使用以下代码在 iPhone 上的 OpenGL ES 2.0 中成功绘制线条。我正在禁用纹理和混合，但我的 GLKBaseEffectsuseConstantColor似乎没有给线条着色 - 它总是黑色的！我无法设置颜色！我怎样才能做到这一点？
// Turn off texturing
self.effect.texture2d0.enabled = NO;
self.effect.texture2d1.enabled = NO;
// Turn off blending
glDisable(GL_BLEND);
glDisable(GL_TEXTURE_2D);
// Draw a line
self.effect.useConstantColor = GL_TRUE;
// Make the line a red color
self.effect.constantColor = GLKVector4Make(
1.0f, // Red
0.0f, // Green
0.0f, // Blue
1.0f);// Alpha
// Prepare the effect for rendering
[self.effect prepareToDraw];
GLfloat line[] = { -1.0, -1.0, -6.0, 1.0, 1.0, 5.0, 1.0, -1.0, 2.0 };
// Create an handle for a buffer object array
GLuint bufferObjectNameArray;
// Have OpenGL generate a buffer name and store it in the buffer object array
glGenBuffers(1, &bufferObjectNameArray);
// Bind the buffer object array to the GL_ARRAY_BUFFER target buffer
glBindBuffer(GL_ARRAY_BUFFER, bufferObjectNameArray);
// Send the line data over to the target buffer in GPU RAM
glBufferData(
GL_ARRAY_BUFFER, // the target buffer
sizeof(line), // the number of bytes to put into the buffer
line, // a pointer to the data being copied
GL_STATIC_DRAW); // the usage pattern of the data
// Enable vertex data to be fed down the graphics pipeline to be drawn
glEnableVertexAttribArray(GLKVertexAttribPosition);
// Specify how the GPU looks up the data
glVertexAttribPointer(
GLKVertexAttribPosition, // the currently bound buffer holds the data
3, // number of coordinates per vertex
GL_FLOAT, // the data type of each component
GL_FALSE, // can the data be scaled
// * INCORRECT * 3, // how many bytes per vertex (3 floats per vertex)
0, // stride (0 bytes between coordinates.) ~Olie
// * INCORRECT * NULL); // offset to the first coordinate, in this case 0
line); // pointer to the buffer to draw. ~Olie
// Set the line width
glLineWidth(5.0);
// Render the line
glDrawArrays(GL_LINE_LOOP, 0, 3);
// Turn on blending
glDisable(GL_BLEND);
// Turn on texturing
self.effect.texture2d0.enabled = YES;
self.effect.texture2d1.enabled = YES;