c++ - OpenGL 黑色纹理

Question

尝试使用位图纹理渲染 2D 标签时，我的纹理采样返回黑色。我尝试使用 RenderDoc 进行调试，但找不到问题所在。看起来纹理加载正常并存储在正确的寄存器中，但它仍然呈现黑色。

我什至尝试使用全红色纹理来检查纹理坐标，但纹理仍然显示为黑色。

这是我用于加载/渲染纹理的代码。它试图渲染标签。 (genMipMaps 为假)。

void Texture::CreateGLTextureWithData(GLubyte* data, bool genMipMaps) {
    if (bitmap)
        glDeleteTextures(1, &bitmap);

    glGenTextures(1, &bitmap);
    glBindTexture(GL_TEXTURE_2D, bitmap);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    if (genMipMaps)
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
    else
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, size.x, size.y, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);

    if (genMipMaps)
        glGenerateMipmap(GL_TEXTURE_2D);
}

自定义采样器:

glGenSamplers(1, &linearSampler);
glSamplerParameteri(linearSampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glSamplerParameteri(linearSampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glSamplerParameteri(linearSampler, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

glSamplerParameteri(linearSampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glSamplerParameteri(linearSampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

glSamplerParameteri(linearSampler, GL_TEXTURE_COMPARE_FUNC, GL_NEVER);

glSamplerParameterf(linearSampler, GL_TEXTURE_MIN_LOD, 0);
glSamplerParameterf(linearSampler, GL_TEXTURE_MAX_LOD, GL_TEXTURE_MAX_LOD);
glBindSampler(0, linearSampler);

渲染:

glDisable(GL_DEPTH_TEST);
glDisable(GL_STENCIL_TEST); 
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);

glActiveTexture(GL_TEXTURE0 + 0);
glBindTexture(GL_TEXTURE_2D, texture->getBitmap());
// Set index and vertex buffers
GLuint vao;
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);


if (glIsBuffer(vertBuffer) && vertBuffer != lastVertBuffer)
    glBindBuffer(GL_ARRAY_BUFFER, vertBuffer);

if (glIsBuffer(indexBuffer) && indexBuffer != lastIndexBuffer)
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);

shader->updateLayout();

// Draw
const void* firstIndex = reinterpret_cast<const void*>(0);
glDrawElements(GL_TRIANGLES, indexCount, GL_UNSIGNED_SHORT, firstIndex);

glBindVertexArray(0);

着色器:

对比:

#version 430 core

// Vertex atributes
in vec3 a_position;
in vec2 a_texture;
in vec4 a_color;


// Constant buffers
layout(std140) uniform VertexBlock
{
    mat4 u_wvp;
    mat4 u_world;
};

// Vertex shader outputs
out vec2 v_texture;
out vec4 v_color;

void main()
{
    v_texture = a_texture;
    v_color = a_color;
    gl_Position = u_wvp * vec4(a_position, 1.0);
}

FS:(我尝试在不使用纹理的情况下将颜色设置为红色，并且它正确地呈现为红色。)

#version 430 core

in vec4 v_color;
in vec2 v_texture;

layout(binding = 0) uniform sampler2D u_texture;

out vec4 fragColor;

void main()
{
    fragColor = v_color * texture(u_texture, v_texture);
}

Answer 1

找出问题所在。我没有为 2D 纹理生成 mipmap，但采样器仍在使用它们。

纹理加载:

...
if (genMipMaps)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
else
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, size.x, size.y, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);

if (genMipMaps)
    glGenerateMipmap(GL_TEXTURE_2D);
...

采样器:

...
glSamplerParameteri(linearSampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glSamplerParameteri(linearSampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
...

我所做的修复就是始终为纹理生成 mipmap