iPhone 上的 OpenGL ES 2.0：GL_POINT_SMOOTH 使用 ES 2.0 绘制正方形，但适用于 ES 1.0

发布于 2024-12-01 20:52:17 字数 1286 浏览 4 评论 0原文

我正在尝试使用顶点缓冲区对象来绘制圆，并在 iPhone 上的 OpenGL ES 2.0 中启用 GL_POINT_SMOOTH 来绘制点。

我已经使用以下 ES 1.0 渲染代码在 iPhone 4 上成功绘制了圆圈：

glVertexPointer(2, GL_FLOAT, 0, circleVertices);
glEnableClientState(GL_VERTEX_ARRAY);
glEnable(GL_POINT_SMOOTH);
glPointSize(radius*2);
glDrawArrays(GL_POINTS, 0, 1);

我现在尝试使用设置 VBO 和此 ES 2.0 渲染代码来实现相同的效果：

glEnable(GL_BLEND); 
glEnable(GL_POINT_SPRITE_OES);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_POINT_SMOOTH);
glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);
glDrawElements(GL_POINTS, numPoints, GL_UNSIGNED_SHORT, BUFFER_OFFSET(0));

但是输出顶点非常明显是正方形，不是圆形。

我尝试减少上面的“glEnable”和相关调用来模拟第一个工作版本，但输出没有发生明显的变化；形状仍然是方形的。我还尝试将“glDrawElements”调用替换为：

    glDrawArrays(GL_POINTS,0,numPoints);

..但同样没有任何变化。

在顶点着色器中设置点大小，并且着色器已成功编译并运行：

uniform mediump mat4 projMx;

attribute vec2 a_position;      
attribute vec4 a_color;     
attribute float a_radius;       
varying vec4 v_color;
void main()
{
    vec4 position = vec4(a_position.x,a_position.y,1.0,1.0);
    gl_Position = projMx * position;
    gl_PointSize = a_radius*2.0;
    v_color = a_color;
}

有谁知道为什么用glDrawElements VBO版本不绘制圆？

原文

I'm trying to draw circles by using a Vertex Buffer Object to draw points with GL_POINT_SMOOTH enabled in OpenGL ES 2.0 on iPhone.

I've used the following ES 1.0 rendering code to draw circles successfully on iPhone 4:

glVertexPointer(2, GL_FLOAT, 0, circleVertices);
glEnableClientState(GL_VERTEX_ARRAY);
glEnable(GL_POINT_SMOOTH);
glPointSize(radius*2);
glDrawArrays(GL_POINTS, 0, 1);

I'm now trying to achieve the same effect using a set-up VBO followed by this ES 2.0 rendering code:

glEnable(GL_BLEND); 
glEnable(GL_POINT_SPRITE_OES);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_POINT_SMOOTH);
glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);
glDrawElements(GL_POINTS, numPoints, GL_UNSIGNED_SHORT, BUFFER_OFFSET(0));

However the output vertices are very clearly square, not circular.

I've tried reducing the 'glEnable' and related calls in the above to emulate the first, working version but no visible change in output occurs; the shapes are still square. I've also tried replacing the 'glDrawElements' call with:

    glDrawArrays(GL_POINTS,0,numPoints);

..but again there's no change.

The point size is set in the vertex shader, and the shader is successfully compiled and run:

uniform mediump mat4 projMx;

attribute vec2 a_position;      
attribute vec4 a_color;     
attribute float a_radius;       
varying vec4 v_color;
void main()
{
    vec4 position = vec4(a_position.x,a_position.y,1.0,1.0);
    gl_Position = projMx * position;
    gl_PointSize = a_radius*2.0;
    v_color = a_color;
}

Does anyone know why circles aren't drawn with the glDrawElements VBO version?

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