Question

我无法弄清楚我做错了什么。这是我的pyopengl代码的相关部分。

首先，我初始化包括采样器和纹理在内的所有内容。 bind_context是我创建的上下文管理器，调用gl.glUseProgram(self.program_index)。

    with self.bind_context():
        # Create sampler.
        self.sampler_object = glGenSamplers(1)

        # Create texture.
        self.texture = gl.glGenTextures(1)

        # Bind sampler to texture unit, and set parameters.
        gl.glActiveTexture(gl.GL_TEXTURE0 + self.texture_unit)
        gl.glBindSampler(self.texture_unit, self.sampler_object)
        gl.glSamplerParameteri(self.sampler_object,
                               gl.GL_TEXTURE_WRAP_S, gl.GL_CLAMP_TO_EDGE)
        gl.glSamplerParameteri(self.sampler_object,
                               gl.GL_TEXTURE_MAG_FILTER, gl.GL_LINEAR)
        gl.glSamplerParameteri(self.sampler_object,
                               gl.GL_TEXTURE_MIN_FILTER, gl.GL_LINEAR)

        # Set uniform with texture unit.
        self.obs_index_to_height(self, self.texture_unit)

偶尔我需要更新纹理，所以我这样做：

def update_texture(self, data):
    # Bind texture to texture unit, set paramters and upload texture.
    # ActiveTexture must precede TexParameter, BindTexture,
    # and TexImage.
    print("Setting", data, data.shape[0])
    gl.glActiveTexture(gl.GL_TEXTURE0 + self.texture_unit)
    gl.glBindTexture(gl.GL_TEXTURE_1D, self.texture)
    gl.glTexImage1D(gl.GL_TEXTURE_1D,
                    0,
                    0x8236,  # gl.GL_R32UI,
                    data.shape[0],
                    0,
                    gl.GL_RED_INTEGER,
                    gl.GL_UNSIGNED_INT,
                    data)

打印：

Setting [      0       1       2       3       4       5       6       7       8       9      10      11       0       0       0       0] 16

我的顶点着色器是

#version 330

uniform mat4 view;
uniform mat4 projection;

uniform vec2 dimensions;
uniform uint obs_index_base;
uniform usampler1D obs_index_to_height;

uniform vec4 color;

in float time;
in uint obs_index;

void main()
{
    float height = int(obs_index + obs_index_base);
    height = texelFetch(
            obs_index_to_height,
            //int(obs_index + obs_index_base),
            int(5),
            0).r;
    gl_Position = projection * view * vec4(time, -height, 0.0, 1.0);
}

从视觉输出中可以清楚地看出，所提取的纹素不是所需的5，而是0。

Answer 1

知道了。我的glGenSamplers正在返回一个列表，我将结果解释为值。我猜这个采样器并没有受到约束。不知道为什么这不会引起错误，或者我怎么会发现错误。

OpenGL usampler1D texelFetch始终返回0

1 个答案: