OpenGL C++，工作几天后纹理突然变黑

Question

打开 GL 3.3

工作了很多天，我的纹理突然变黑了几乎所有有类似问题的帖子都是关于不正确或没有使用 glTexParameteri 或 不正确的纹理加载 但我似乎在这方面做的一切都是正确的，包含数据的向量是 1024 字节（16 像素 x 16 像素 x 4 字节）所以很好，问题出现后，我做了一个测试纹理，只是为了确保一切都是正确的。还看到许多帖子问题是不完整的纹理，但这里我使用glTexImage2D传递数据，因此纹理必须完整，而且不创建mipmaps，我禁用了它们进行测试。虽然他们在这个错误之前就已经开始工作了。

我也经常调用 glGetError 并且没有错误

这里是纹理创建代码：

unsigned int testTexture;
unsigned long w, h;
std::vector<byte> data;
std::vector<byte> img;
loadFile(data, "./assets/textures/blocks/brick.png");
decodePNG(img, w, h, &data[0], data.size());
glGenTextures(1, &testTexture);
glBindTexture(GL_TEXTURE_2D, testTexture);
glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA8,w,h,0,GL_RGBA, GL_UNSIGNED_BYTE,&img[0]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
data.clear();
img.clear();

这里是我设置制服:

glUseProgram(worldShaderProgram);
glUniform1f(glGetUniformLocation(worldShaderProgram, "time"), gameTime);
glUniformMatrix4fv(glGetUniformLocation(worldShaderProgram, "MVP"), 1, GL_FALSE, &TheMatrix[0][0]);
glUniform1i(glGetUniformLocation(worldShaderProgram, "texAtlas"), testTexture);
glUniform1f(glGetUniformLocation(worldShaderProgram, "texMult"), 16.0f / 256.0f);
glUniform4f(glGetUniformLocation(worldShaderProgram, "fogColor"), fogColor.r, fogColor.g, fogColor.b, fogColor.a);

还有片段着色器

#version 330

in vec4 tex_color;
in vec2 tex_coord;

layout(location = 0) out vec4 color;

uniform sampler2D texAtlas;
uniform mat4 MVP;
uniform vec4 fogColor;

const float fogStart = 0.999f;
const float fogEnd = 0.9991f;
const float fogMult = 1.0f / (fogEnd - fogStart);

void main() {
    if (gl_FragCoord.z >= fogEnd)
        discard;

    //color = vec4(tex_coord.x,tex_coord.y,0.0f,1.0f) * tex_color; // This Line Does What Its Supposed To
    color = texture(texAtlas,tex_coord) * tex_color; // This One Does Not

    if (gl_FragCoord.z >= fogStart)
        color = mix(color,fogColor,(gl_FragCoord.z - fogStart) * fogMult);
}

如果我使用这条线 color = vec4(tex_coord.x,tex_coord.y,0.0f,1.0f) * tex_color;

代替这一行color = texture(texAtlas,tex_coord) * tex_color;

要显示来自的坐标，它将从纹理中获取其颜色，结果就是您所期望的：（Currenlty 仅使用顶面对其进行测试)

Image Link Cause I Cant Do Images But Please Click

证明顶点着色器工作正常 (sampler2D是在fragment shader处从uniform得到的)

主循环渲染代码

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBindTexture(GL_TEXTURE_2D, textures.textureId);
glUseProgram(worldShaderProgram);
wm.render();
// wm.render() calls lots of meshes to render themselves
// just wanted to point out each one of them has their own
// vertex arry buffer, vertex buffer, and index buffer
// to render i bind the vertex array buffer with glBindVertexArray(vertexArrayBuffer);
// then i call glDrawElements();

这里还有 OpenGL 初始化代码

if (!glfwInit()) // Initialize the library
    return -1;

window = glfwCreateWindow(wndSize.width, wndSize.height, "Minecraft", NULL, NULL);

if (!window)
{
    glfwTerminate();
    return -1;
}

glfwMakeContextCurrent(window); // Make the window's context current
glfwSetWindowSizeCallback(window,resiseEvent);

glfwSwapInterval(1);

if (glewInit() != GLEW_OK)
    return -1;

glClearColor(fogColor.r, fogColor.g, fogColor.b, fogColor.a);
glClearDepth(1.0f);
glEnable(GL_DEPTH_TEST); // Enable depth testing for z-culling
glEnable(GL_CULL_FACE); // Orientation Culling
glDepthFunc(GL_LEQUAL);    // Set the type of depth-test (<=)
glShadeModel(GL_SMOOTH);   // Enable smooth shading
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);  // Nice perspective corrections
glLineWidth(2.0f);

Answer 1

您错误地将纹理对象设置为纹理采样器统一。这是错误的：

glUniform1i(glGetUniformLocation(worldShaderProgram, "texAtlas"), testTexture);

纹理对象和纹理采样器统一之间的绑定点是纹理单元。当glBindTexture is invoked, then the texture object is bound to the specified target and the current texture unit. The texture unit can be chosen by glActivTexture。默认纹理单位是 GL_TEXTURE0.

由于您的纹理绑定到纹理单元 0 (GL_TEXTURE0)，您已将值 0 设置为纹理采样器统一：

glUniform1i(glGetUniformLocation(worldShaderProgram, "texAtlas"), 0);

请注意，您的代码之前是偶然工作的。您只有 1 个纹理对象或 testTexture 是创建的第一个纹理名称。因此 testTexture 的值是 0。现在 testTexture 的值不再是 0，导致您的代码失败。

OpenGL C++，工作几天后纹理突然变黑

OpenGL C++, Textures Suddenly Black After Being Working For Days

c++

opengl

textures

glew

glfw