TGA and RGB image loading

CMakeLists.txt

@@ -11,7 +11,7 @@ if(NOT ${OPENGL_GLU_FOUND})
 endif()
 
 add_executable(tests_opengl
-        src/main.cpp src/displayers.h src/displayers.cpp)
+        src/main.cpp src/displayers.h src/displayers.cpp src/Texture.cpp src/Texture.h)
 
 target_link_libraries(tests_opengl
         ${OPENGL_LIBRARIES}

src/Texture.cpp

@@ -0,0 +1,80 @@
+//
+// Created by trotfunky on 24/09/2019.
+//
+
+#include "Texture.h"
+
+
+Texture::Texture() : width(0), height(0), color_bits(0), image_data(nullptr), opengl_id{(uint32_t)-1}
+{}
+
+Texture::~Texture()
+{
+    if (opengl_id[0] != (uint32_t)-1)
+    {
+        delete(image_data);
+        glDeleteTextures(1,opengl_id);
+    }
+}
+
+bool Texture::load_tga(const std::string& filename, uint8_t*& data_array)
+{
+    std::fstream file_stream(filename,std::ios_base::in|std::ios_base::binary);
+    if (file_stream.fail())
+    {
+        std::cerr << "Error while opening " <<  filename << std::endl;
+        return false;
+    }
+
+    // Length of the image ID
+    uint8_t id_length = 0;
+    file_stream >> id_length;
+
+    file_stream.seekg(1,std::ios_base::cur);
+    uint8_t tga_data_type = 0;
+    file_stream >> tga_data_type;
+
+    // Only supported type : Raw RGB data
+    if (tga_data_type != 2)
+    {
+        std::cerr << "Error loading file " << filename << ": Unsupported format " << tga_data_type << std::endl;
+        file_stream.close();
+        return false;
+    }
+
+    // Place the cursor to the position of the width header data
+    file_stream.seekg(12,std::ios_base::beg);
+    file_stream.read((char*)&width,2);
+    file_stream.read((char*)&height,2);
+    file_stream >> color_bits;
+
+    if (color_bits != 24 && color_bits != 32)
+    {
+        std::cerr << "Error loading file " << filename << ": Unsupported " << color_bits << " bits colors" << std::endl;
+        file_stream.close();
+        return false;
+    }
+
+    // Move cursor to the end to get file size
+    file_stream.seekg(0,std::ios_base::end);
+    // Size of the file minus header length minus ID length
+    int data_length = width*height*(color_bits/8);
+
+    // Move cursor to the start of the data.
+    file_stream.seekg(18+id_length,std::ios_base::beg);
+
+    data_array = new uint8_t[data_length];
+    file_stream.read((char*)data_array,data_length);
+
+    return true;
+}
+
+bool Texture::load_rgb_tga(const std::string& rgb_filename)
+{
+    return load_tga(rgb_filename,image_data);
+}
+
+bool Texture::load_rgba_tga(const std::string& rgb_filename,const std::string& mask_filename)
+{
+    return false;
+}

src/Texture.h

@@ -0,0 +1,38 @@
+//
+// Created by trotfunky on 24/09/2019.
+//
+
+#ifndef TESTS_OPENGL_TEXTURE_H
+#define TESTS_OPENGL_TEXTURE_H
+
+#include <GL/glut.h>
+#include <string>
+#include <fstream>
+#include <iostream>
+
+class Texture {
+public:
+    uint16_t width;
+    uint16_t height;
+
+    /// Number of bits describing the colors : 24 (RGB) or 32 (RGBA)
+    uint8_t color_bits;
+
+    uint8_t* image_data;
+    uint32_t opengl_id[1];
+
+    Texture();
+    ~Texture();
+
+    /// Load an RGBA image from an RGB TGA file
+    bool load_rgb_tga(const std::string& rgb_filename);
+    /// Load an RGBA image from an rgb and an alpha tga file
+    bool load_rgba_tga(const std::string& rgb_filename,const std::string& mask_filename);
+
+private:
+    /// Load TGA image file to an array
+    bool load_tga(const std::string& filename, uint8_t*& data_array);
+};
+
+
+#endif //TESTS_OPENGL_TEXTURE_H

src/displayers.cpp

@@ -60,17 +60,39 @@ void display_rotating_pyramid(float x, float y, float z, float c, float h, float
     glPopMatrix();
 }
 
-void display_tree(float x, float y, float z, float h, float w)
+void display_tree(float x, float y, float z, float h, float w, const Texture& tree_texture)
 {
+    glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
+    glBindTexture(GL_TEXTURE_2D,tree_texture.opengl_id[0]);
+
+    glColor4f(1.0f, 1.0f, 1.0f,1.00);
     glBegin(GL_QUADS);
+
+    // First rectangle
+    glTexCoord2f(1,0);
     glVertex3f(x+w/2,y,z);
+
+    glTexCoord2f(0,0);
     glVertex3f(x-w/2,y,z);
+
+    glTexCoord2f(0,1);
     glVertex3f(x-w/2,y+h,z);
+
+    glTexCoord2f(1,1);
     glVertex3f(x+w/2,y+h,z);
 
+    // Second rectangle
+    glTexCoord2f(1,0);
     glVertex3f(x,y,z+w/2);
+
+    glTexCoord2f(0,0);
     glVertex3f(x,y,z-w/2);
+
+    glTexCoord2f(0,1);
     glVertex3f(x,y+h,z-w/2);
+
+    glTexCoord2f(1,1);
     glVertex3f(x,y+h,z+w/2);
+
     glEnd();
 }

src/displayers.h

@@ -7,6 +7,8 @@
 
 #include <GL/glut.h>
 
+#include "Texture.h"
+
 /// Displays a square based pyramid from a base position, height and side length
 /// \param x X coordinate of the center
 /// \param y Y coordinate of the center
@@ -19,6 +21,6 @@ void display_pyramid(float x, float y, float z, float c, float h);
 void display_rotating_pyramid(float x, float y, float z, float c, float h, float alpha);
 
 /// Draw a tree with two quadrilaterals
-void display_tree(float x, float y, float z, float h, float w);
+void display_tree(float x, float y, float z, float h, float w, const Texture& tree_texture);
 
 #endif //TESTS_OPENGL_DISPLAYERS_H

src/main.cpp

@@ -1,8 +1,12 @@
 #include "GL/glut.h"
+#include "GL/gl.h"
 
 #include "displayers.h"
+#include "Texture.h"
+
 
 volatile unsigned long long int timer_ticks = 0;
+static Texture tree_texture;
 
 void display()
 {
@@ -25,6 +29,8 @@ void display()
     display_rotating_pyramid(5,-2,0,1,5,angleY);
     display_rotating_pyramid(-2,-2,4,3,2,angleY);
 
+    display_tree(0,-5,0,3,5,tree_texture);
+
     glutSwapBuffers();
 }
 
@@ -48,6 +54,24 @@ int main(int argc, char** argv)
 //    glEnable(GL_LIGHT0);
     glEnable(GL_DEPTH_TEST);
 
+    // Setup OPenGL to use textures
+    glEnable(GL_TEXTURE_2D);
+    glEnable(GL_ALPHA_TEST);
+    glAlphaFunc(GL_GREATER, 0.5);
+
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT/GL_CLAMP);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT/GL_CLAMP);
+    glTexEnvi(GL_TEXTURE_2D, GL_TEXTURE_ENV_MODE, GL_MODULATE);
+
+    // Load and generate tree texture
+    tree_texture.load_rgb_tga("resources/arbre.tga");
+    glGenTextures(1,tree_texture.opengl_id);
+    glBindTexture(GL_TEXTURE_2D,tree_texture.opengl_id[0]);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, tree_texture.width,tree_texture.height,0,GL_RGB,GL_UNSIGNED_BYTE,tree_texture.image_data);
+    gluBuild2DMipmaps(GL_TEXTURE_2D,GL_RGB8,tree_texture.width,tree_texture.height,GL_RGB,GL_UNSIGNED_BYTE,tree_texture.image_data);
+
     glViewport(0,0,glutGet(GLUT_WINDOW_WIDTH),glutGet(GLUT_WINDOW_HEIGHT));
 
     glutIdleFunc(display);