# Work at gfx driver system

- Update pool to use template allocator directly instead of std::vector
- Add a GfxDriver config Template to be able to modify settings like allocators / Types for specific Drivers
- Add glad

backends/CMakeLists.txt

@@ -0,0 +1,21 @@
+cmake_minimum_required(VERSION 3.22)
+
+project(pd-system)
+
+option(PD_ENABLE_OPENGL2 "Enable OpenGL 2.1 (On Supported Hardware)" ON)
+option(PD_ENABLE_OPENGL3 "Enable OpenGL 3.3 (On Supported Hardware)" ON)
+option(PD_ENABLE_VULKAN "Not implemented yet" OFF)
+
+add_library(pd-system STATIC
+    ${CMAKE_CURRENT_SOURCE_DIR}/source/gfx_opengl.cpp
+)
+target_include_directories(pd-system
+    PUBLIC
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+    $<INSTALL_INTERFACE:include>
+)
+target_link_libraries(pd-system
+    PUBLIC
+    palladium::palladium
+    glad
+)

backends/include/gfx_opengl.hpp

@@ -0,0 +1,42 @@
+#pragma once
+
+#include <pd/drivers/gfx.hpp>
+
+namespace PD {
+struct GfxOpenGLConfig {
+  // Vertex Allocator
+  template <typename T>
+  using VertexAlloc = std::allocator<T>;
+  // Index Allocator
+  template <typename T>
+  using IndexAlloc = std::allocator<T>;
+  using IndexType = u32;  // Index Type
+
+  static constexpr size_t NumVertices = 32768;  // 8192*4
+  static constexpr size_t NumIndices = 49152;   // 8192*6
+};
+class GfxOpenGL : public GfxDriverBase<GfxOpenGLConfig> {
+ public:
+  GfxOpenGL() {}
+  ~GfxOpenGL() {}
+
+  void SysInit() override;
+  void SysDeinit() override;
+  void Submit(size_t count, size_t start) override;
+  void BindTexture(TextureID id) override;
+  void SysReset() override;
+  TextureID LoadTexture(const std::vector<PD::u8>& pixels, int w, int h,
+                        TextureFormat type = TextureFormat::RGBA32,
+                        TextureFilter filter = TextureFilter::Linear) override;
+  void DeleteTexture(const TextureID& tex) override;
+
+ private:
+  void pSetupShaderAttribs(u32 shader);
+  u32 pShader = 0;
+  u32 VBO = 0;
+  u32 IBO = 0;
+  int pLocTex = 0;
+  int pLocAlfa = 0;
+  int pLocProjection = 0;
+};
+}  // namespace PD

backends/source/gfx_opengl.cpp

@@ -0,0 +1,154 @@
+#include <glad/glad.h>
+
+#include <gfx_opengl.hpp>
+
+namespace PD {
+GLuint compileShader(const std::string& source, GLenum type) {
+  GLuint shader = glCreateShader(type);
+  const char* src = source.c_str();
+  glShaderSource(shader, 1, &src, nullptr);
+  glCompileShader(shader);
+
+  GLint success;
+  glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
+  if (!success) {
+    char infoLog[512];
+    glGetShaderInfoLog(shader, 512, nullptr, infoLog);
+    std::cerr << "Shader Compilation Error: " << infoLog << std::endl;
+  }
+
+  return shader;
+}
+
+GLuint createShaderProgram(const std::string& vertexShaderSource,
+                           const std::string& fragmentShaderSource) {
+  GLuint vertexShader = compileShader(vertexShaderSource, GL_VERTEX_SHADER);
+  GLuint fragmentShader =
+      compileShader(fragmentShaderSource, GL_FRAGMENT_SHADER);
+
+  GLuint shaderProgram = glCreateProgram();
+  glAttachShader(shaderProgram, vertexShader);
+  glAttachShader(shaderProgram, fragmentShader);
+  glLinkProgram(shaderProgram);
+
+  GLint success;
+  glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
+  if (!success) {
+    char infoLog[512];
+    glGetProgramInfoLog(shaderProgram, 512, nullptr, infoLog);
+    std::cerr << "Shader Program Linking Error: " << infoLog << std::endl;
+  }
+
+  glDeleteShader(vertexShader);
+  glDeleteShader(fragmentShader);
+
+  return shaderProgram;
+}
+
+const char* vertex_shader = R"(
+  #version 120
+  
+  attribute vec2 pos;
+  attribute vec2 uv;
+  attribute vec4 color;
+  
+  varying vec2 oUV;
+  varying vec4 oColor;
+  
+  // Probably forgot about this matrix and
+  // searched hours for why the rendering isn't working :/
+  uniform mat4 projection;
+  
+  void main() {
+      gl_Position = projection*vec4(pos, 0.0, 1.0);
+      oUV = uv;
+      oColor = color;
+  }
+  )";
+
+const char* frag_shader = R"(
+  #version 120
+      
+  varying vec2 oUV;
+  varying vec4 oColor;
+  
+  uniform sampler2D tex;
+  uniform bool alfa;
+      
+  void main() {
+    vec4 tc = texture2D(tex, oUV);
+    if (alfa) {
+      gl_FragColor = vec4(oColor.rgb, tc.a * oColor.a);
+    } else {
+      gl_FragColor = tc * oColor;
+    }
+  }
+  )";
+
+void GfxOpenGL::pSetupShaderAttribs(u32 shader) {
+  GLint _pos = glGetAttribLocation(shader, "pos");
+  GLint _uv = glGetAttribLocation(shader, "uv");
+  GLint _color = glGetAttribLocation(shader, "color");
+  glVertexAttribPointer(_pos, 2, GL_FLOAT, GL_FALSE, sizeof(PD::Li::Vertex),
+                        (void*)offsetof(PD::Li::Vertex, pos));
+  glEnableVertexAttribArray(_pos);
+
+  glVertexAttribPointer(_uv, 2, GL_FLOAT, GL_FALSE, sizeof(PD::Li::Vertex),
+                        (void*)offsetof(PD::Li::Vertex, uv));
+  glEnableVertexAttribArray(_uv);
+
+  glVertexAttribPointer(_color, 4, GL_UNSIGNED_BYTE, GL_TRUE,
+                        sizeof(PD::Li::Vertex),
+                        (void*)offsetof(PD::Li::Vertex, color));
+  glEnableVertexAttribArray(_color);
+}
+
+void GfxOpenGL::SysInit() {
+  pShader = createShaderProgram(vertex_shader, frag_shader);
+  glUseProgram(pShader);
+  glGenBuffers(1, &VBO);
+  glBindBuffer(GL_ARRAY_BUFFER, VBO);
+  pSetupShaderAttribs(pShader);
+  glGenBuffers(1, &IBO);
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IBO);
+
+  pLocTex = glGetUniformLocation(pShader, "tex");
+  pLocAlfa = glGetUniformLocation(pShader, "alfa");
+  pLocProjection = glGetUniformLocation(pShader, "projection");
+
+  glBindBuffer(GL_ARRAY_BUFFER, 0);
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+}
+
+void GfxOpenGL::SysDeinit() {
+  glDeleteBuffers(1, &VBO);
+  glDeleteBuffers(1, &IBO);
+}
+
+void GfxOpenGL::Submit(size_t count, size_t start) {
+  glDrawElements(GL_TRIANGLES, count, GL_UNSIGNED_INT,
+                 (void*)GetIndexBufPtr(start));
+}
+
+void GfxOpenGL::BindTexture(TextureID id) {
+  glActiveTexture(GL_TEXTURE0);
+  glBindTexture(GL_TEXTURE_2D, (GLuint)id);
+  glUniform1i(pLocTex, 0);
+  GLint fmt = 0;
+  glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_INTERNAL_FORMAT, &fmt);
+  glUniform1i(pLocAlfa, fmt == GL_ALPHA);
+}
+
+void GfxOpenGL::SysReset() {}
+
+TextureID GfxOpenGL::LoadTexture(const std::vector<PD::u8>& pixels, int w,
+                                 int h, TextureFormat type,
+                                 TextureFilter filter) {
+  return 0;
+}
+
+void GfxOpenGL::DeleteTexture(const TextureID& tex) {
+  GLuint tex_ = tex;
+  glDeleteTextures(1, &tex_);
+}
+}  // namespace PD