OpenGL的新功能,我使用GL_LINE_LOOP在iOS 5上使用GLKit成功显示行,但使用GL_POINTS显示点给我带来了麻烦。具体来说,除了单个像素,我无法显示任何内容。我在网上搜索没有成功,所以我希望有人可以指出我缺少的东西。
这是我的测试代码......
//positions and colors, vertices and indices...
typedef struct {
float Position[2];
float Color[4];
} Vertex;
const Vertex Vertices[] = {
{{50, 50}, {0, 0, 1, 1}},
{{200, 50}, {0, 0, 1, 1}},
{{200, 200}, {0, 0, 1, 1}},
{{50, 200}, {0, 0, 1, 1}}
};
const GLubyte Indices[] = {
0, 1, 2, 3
};
@interface AppViewController() {
GLuint _vertexBuffer;
GLuint _indexBuffer;
}
...
//some unrelated properties, the @implementation and other methods
...
- (void)viewDidLoad {
[super viewDidLoad];
self.context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
if (!self.context) NSLog(@"Failed to create ES context");
GLKView *view = (GLKView *)self.view;
view.context = self.context;
[EAGLContext setCurrentContext:self.context];
self.effect = [[GLKBaseEffect alloc] init];
GLKMatrix4 projectionMatrix = GLKMatrix4MakeOrtho(0, self.view.bounds.size.width, 0, self.view.bounds.size.height, -1024, 1024);
self.effect.transform.projectionMatrix = projectionMatrix;
glGenBuffers(1, &_vertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices), Vertices, GL_STATIC_DRAW);
glGenBuffers(1, &_indexBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _indexBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(Indices), Indices, GL_STATIC_DRAW);
}
- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect {
glClearColor(1, 1, 1, 1);
glClear(GL_COLOR_BUFFER_BIT);
[self.effect prepareToDraw];
glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _indexBuffer);
glEnableVertexAttribArray(GLKVertexAttribPosition);
glVertexAttribPointer(GLKVertexAttribPosition, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, Position));
glEnableVertexAttribArray(GLKVertexAttribColor);
glVertexAttribPointer(GLKVertexAttribColor, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, Color));
//this worked for drawing my lines...
//glLineWidth(10);
//glDrawElements(GL_LINE_LOOP, sizeof(Indices)/sizeof(Indices[0]), GL_UNSIGNED_BYTE, 0);
//this does NOT work for drawing 10-pixel points. single pixel only.
glEnable(GL_POINT_SMOOTH);
glPointSize(10);
glDrawElements(GL_POINTS, sizeof(Indices)/sizeof(Indices[0]), GL_UNSIGNED_BYTE, 0);
}
谢谢你的时间!
答案 0 :(得分:7)
我不认为glPointSize()
是OpenGL ES 2.0的一部分。
尝试设置......
gl_PointSize = 10.0; //has to be a floating point value
...在你的顶点着色器中。