you can now print images on the screen

CMakeLists.txt

@@ -12,7 +12,8 @@ add_executable(${PROJECT_NAME} src/main.cpp
         include/defines.hpp
         src/Shader.cpp
         include/Shader.hpp
-        include/IndexBuffer.hpp)
+        include/IndexBuffer.hpp
+        libs/stb_image.hpp)
 
 target_compile_definitions(${PROJECT_NAME} PRIVATE $<$<CONFIG:Debug>:_DEBUG>)
 

include/VertexBuffer.hpp

@@ -15,9 +15,12 @@ struct VertexBuffer {
         // POSITION
         glEnableVertexAttribArray(0);
         glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*) offsetof(Vertex,x));
-        // COLOR
+        // TEXTURE COORDINATES
         glEnableVertexAttribArray(1);
-        glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*) offsetof(Vertex,r));
+        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*) offsetof(Vertex,u));
+        // COLOR
+        glEnableVertexAttribArray(2);
+        glVertexAttribPointer(2, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*) offsetof(Vertex,r));
 
         glBindVertexArray(0);
     };

include/defines.hpp

@@ -16,5 +16,6 @@ typedef double float64;
 
 struct Vertex {
     float32 x, y, z;        // position
+    float32 u, v;           // texture coordinates
     float32 r, g, b, a;     // color
 };

shaders/basic.frag

@@ -3,9 +3,12 @@
 layout(location = 0) out vec4 f_color;
 
 in vec4 v_color;
+in vec2 v_texCoord;
+uniform sampler2D u_texture;
 
 uniform vec4 u_color;
 
 void main() {
-    f_color = u_color;
+    vec4 texColor = texture(u_texture, v_texCoord);
+    f_color = texColor;
 }

shaders/basic.vert

@@ -1,11 +1,14 @@
 #version 330 core
 
 layout(location = 0) in vec3 a_position;
-layout(location = 1) in vec4 a_color;
+layout(location = 1) in vec2 a_texCoord;
+layout(location = 2) in vec4 a_color;
 
 out vec4 v_color;
+out vec2 v_texCoord;
 
 void main() {
     gl_Position = vec4(a_position, 1.0f);
     v_color = a_color;
+    v_texCoord = a_texCoord;
 }

src/main.cpp

@@ -8,6 +8,8 @@
 #include "IndexBuffer.hpp"
 #include "VertexBuffer.hpp"
 #include "Shader.hpp"
+#define STB_IMAGE_IMPLEMENTATION
+#include "../libs/stb_image.hpp"
 
 void openGLDebugCallback(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar* message, const void* userParam) {
     if (severity == GL_DEBUG_SEVERITY_NOTIFICATION) return; //ignore notifications (mostly performance information)
@@ -100,11 +102,19 @@ int main() {
     #endif
 
     Vertex vertices[] = {
-        Vertex{-0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f},
-        Vertex{-0.5f, 0.5f, 0.0f, 0.0, 1.0f, 0.0f, 1.0f},
-        Vertex{0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f},
+        Vertex{-0.5f, -0.5f, 0.0f,
+            0.0f, 0.0f,
+            1.0f, 0.0f, 0.0f, 1.0f},
+        Vertex{-0.5f, 0.5f, 0.0f,
+            0.0f, 1.0f,
+            0.0, 1.0f, 0.0f, 1.0f},
+        Vertex{0.5f, -0.5f, 0.0f,
+            1.0f, 0.0f,
+            0.0f, 0.0f, 1.0f, 1.0f},
 
-        Vertex{0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f},
+        Vertex{0.5f, 0.5f, 0.0f,
+            1.0f, 1.0f,
+            1.0f, 0.0f, 0.0f, 1.0f},
     };
     uint32 numVertices = sizeof(vertices) / sizeof(Vertex);
 
@@ -119,6 +129,28 @@ int main() {
     VertexBuffer vertexBuffer(vertices, numVertices);
     vertexBuffer.unbind();
 
+    int32 textureWidth = 0;
+    int32 textureHeight = 0;
+    int32 bitsPerPixel = 0;
+    stbi_set_flip_vertically_on_load(true);
+    auto textureBuffer = stbi_load("../assets/logo.png", &textureWidth, &textureHeight, &bitsPerPixel, 4);
+
+    GLuint textureId;
+    glGenTextures(1, &textureId);
+    glBindTexture(GL_TEXTURE_2D, textureId);
+
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // or GL_NEAREST for pixel like style (instead of GL_LINEAR -> interpolation)
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, textureWidth, textureHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureBuffer);
+    glBindTexture(GL_TEXTURE_2D, 0);
+
+    if (textureBuffer) {
+        stbi_image_free(textureBuffer);
+    }
+
     Shader shader("shaders/basic.vert", "shaders/basic.frag");
     shader.bind();
 
@@ -127,6 +159,11 @@ int main() {
         glUniform4f(colorUniformLocation, 1.0f, 0.0f, 1.0f, 1.0f);
     }
 
+    int textureUniformLocation = glGetUniformLocation(shader.getShaderId(), "u_texture");
+    if (textureUniformLocation != 1) {
+        glUniform1i(textureUniformLocation, 0);
+    }
+
     const uint64 perfCounterFrequency = SDL_GetPerformanceFrequency();
     uint64 lastCounter = SDL_GetPerformanceCounter();
     float32 delta = 0.0f;
@@ -150,6 +187,8 @@ int main() {
         // FRAME GENERATION
         vertexBuffer.bind();
         indexBuffer.bind();
+        glActiveTexture(GL_TEXTURE0);
+        glBindTexture(GL_TEXTURE_2D, textureId);
         glDrawElements(GL_TRIANGLES, numIndices, GL_UNSIGNED_INT, 0);
         vertexBuffer.unbind();
         indexBuffer.unbind();
@@ -170,6 +209,8 @@ int main() {
         lastCounter = endCounter;
     }
 
+    glDeleteTextures(1, &textureId);
+
     SDL_GL_DestroyContext(context);
     SDL_DestroyWindow(window);
     SDL_Quit();