OpenGLTexture.cpp

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#include "Engine/Texture/OpenGLTexture.hpp"
#ifdef USING_OPENGL
#include "Engine/Utility/Utility.hpp"

#include <ThirdParty/glew-2.1.0/include/GL/glew.h>

namespace Engine
{
    OpenGLTexture::OpenGLTexture(const eastl::string& filename, int desiredChannels) : Texture(filename, desiredChannels)
    {
        eastl::string baseLocation = "Resources/Textures/";
        baseLocation.append(filename);
        stbi_uc* textureData = stbi_load(
            Utility::FileExists(baseLocation) ?
            baseLocation.c_str() :
            "Resources/Textures/default.png", &width, &height, &channels, STBI_rgb_alpha);
        OpenGLTexture::CreateTextureWithData(textureData, true);
        stbi_image_free(textureData);
    }

    OpenGLTexture::OpenGLTexture(int width, int height) : Texture(width, height)
    {
    }

    OpenGLTexture::~OpenGLTexture()
    {
        GLuint textureReference = GLuint(texture);

        if (texture)
            glDeleteTextures(1, &textureReference);
    }

    void OpenGLTexture::CreateTextureWithData(stbi_uc* data, bool genMipMaps, TextureDataSize bytes, bool storage)
    {
        this->dataSize = bytes;
        GLuint textureReference = GLuint(texture);
        if (textureReference)
            glDeleteTextures(1, &textureReference);

        glGenTextures(1, &textureReference);                                    // Gen    
        glGetError();

        glBindTexture(GL_TEXTURE_2D, textureReference);                          // Bind
        glGetError();

        //
        if (genMipMaps)
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);    // Minmization
        else
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);                   // Minmization
        glGetError();

        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);                       // Magnification
        glGetError();

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

        GLenum type;

        switch (bytes) {
        case TextureDataSize::U_CHAR:
            type = GL_UNSIGNED_BYTE;
            break;
        case TextureDataSize::S_CHAR:
            type = GL_UNSIGNED_BYTE;
            break;
        case TextureDataSize::U_SHORT:
            type = GL_UNSIGNED_SHORT;
            break;
        case TextureDataSize::S_SHORT:
            type = GL_UNSIGNED_SHORT;
            break;
        case TextureDataSize::U_INT:
            type = GL_UNSIGNED_INT;
            break;
        case TextureDataSize::S_INT:
            type = GL_UNSIGNED_INT;
            break;
        default:
            type = GL_UNSIGNED_BYTE;
            break;
        }

        glTexImage2D(
            GL_TEXTURE_2D,                      // What (target)
            0,                                  // Mip-map level
            GL_RGBA,                            // Internal format
            width,                              // Width
            height,                             // Height
            0,                                  // Border
            GL_RGBA,                            // Format (how to use)
            type,                   // Type   (how to intepret)
            data);                              // Data
        glGetError();

        if (genMipMaps)
            glGenerateMipmap(GL_TEXTURE_2D);

        glGetError();

        texture = uint64_t(textureReference);
    }
} //namespace Engine
#endif