[英]How to properly load an image to use as an OpenGL texture?
我正在嘗試使用SOIL2將圖像加載到OpenGL紋理中; 但是,除非我使用SOIL2的紋理加載功能,否則這似乎是不正確的。 我嘗試使用機頂盒圖像和Devil,但兩者都得到相似的結果。
碼:
GLuint load_image(const std::string& path) {
int iwidth, iheight, channels;
unsigned char* image = SOIL_load_image(path.c_str(), &iwidth, &iheight, &channels, SOIL_LOAD_RGBA);
// std::cout << SOIL_last_result() << std::endl;
// float* image = stbi_loadf(path.c_str(), &iwidth, &iheight, &channels, STBI_rgb_alpha);
// if(!ilLoadImage(path.c_str()))
// std::cout << "Devil Failed to load image: " << iluErrorString(ilGetError()) << std::endl;
//
// unsigned char* image = ilGetData();
//
// int iwidth = ilGetInteger(IL_IMAGE_WIDTH);
// int iheight = ilGetInteger(IL_IMAGE_HEIGHT);
// int channels = ilGetInteger(IL_IMAGE_CHANNELS);
GLuint texture;
glGenTextures(1, &texture);
glActiveTexture(GL_TEXTURE0 + texture);
GLint old_unpack_alignment;
glGetIntegerv(GL_UNPACK_ALIGNMENT, &old_unpack_alignment);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glBindTexture(GL_TEXTURE_2D, texture);
glCheckError();
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glCheckError();
GLenum original_format = (channels == 4 ? GL_RGBA : GL_RGB);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
glGenerateMipmap(GL_TEXTURE_2D);
glPixelStorei(GL_UNPACK_ALIGNMENT, old_unpack_alignment);
return texture;
}
屏幕截圖:
我應該得到什么:
我想知道如何正確地將圖像加載到紋理中。
這是我的紋理加載功能的示例:
unsigned int loadTexture(char const * path)
{
unsigned int textureID;
glGenTextures(1, &textureID);
int width, height, nrComponents;
unsigned char *data = stbi_load(path, &width, &height, &nrComponents, 0);
if (data)
{
GLenum format;
if (nrComponents == 1)
format = GL_RED;
else if (nrComponents == 3)
format = GL_RGB;
else if (nrComponents == 4)
format = GL_RGBA;
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
glGenerateMipmap(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, format == GL_RGBA ? GL_CLAMP_TO_EDGE : GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, format == GL_RGBA ? GL_CLAMP_TO_EDGE : GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
stbi_image_free(data);
}
else
{
std::cout << "Texture failed to load at path: " << path << std::endl;
stbi_image_free(data);
}
return textureID
}
通常,我會先手動設置VAO和VBO,然后再使用它來加載紋理。 此后,我將配置我的着色器以供使用,然后在渲染循環中使用着色器,設置要傳遞的矩陣,傳遞所需的任何制服,然后在完成所有“模型”信息后,最后,將綁定VertexArrays,將適當的紋理設置為Active,然后將這些紋理綁定,然后繪制數組或基元進行繪制。
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