First opengl animation

main.cpp

@@ -58,6 +58,24 @@ bool TestGame::tick()
     if (ev.type == SDL_QUIT)
       return false;
   }
+  //Calculate colors
+  if(state.bright)
+    state.brightness+=0.001;
+  else
+    state.brightness-=0.001;
+  if(state.bright && state.brightness >= 1.0)
+    state.bright=false;
+  if(!state.bright && state.brightness < 0.0)
+    state.bright=true;
+  //Apply colors
+  GLfloat triangle_colors[] = {
+    state.brightness, 0.0, 0.0,
+    0.0, state.brightness, 0.0,
+    0.0, 0.0, state.brightness,
+  };
+  t1.update(triangle_colors, sizeof(triangle_colors));
+  t2.update(triangle_colors, sizeof(triangle_colors));
+  t3.update(triangle_colors, sizeof(triangle_colors));
   render();
   return true;
 }

main.h

@@ -2,6 +2,7 @@
 #include <renderer/shader.h>
 #include <renderer/shapes/triangle.h>
 #include <GL/glew.h>
+#include <state.h>
 class TestGame: public MainClass {
 private:
   Triangle t1, t2, t3;
@@ -11,11 +12,15 @@ private:
   VertexShader *vs;
   FragmentShader *fs;
   GLint attribute_v_color;
+  GameState state;
 protected:
   virtual auto tick() -> bool;
   virtual auto init() -> bool;
 public:
-  TestGame(): MainClass(640,480), t1(0.0, 0.0, 0.5, 1.0, 1.0, 0.0), t2(1.0,0.0,1.5,1.0,2.0,0.0), t3(0.5,1.0,1.0,2.0,1.5,1.0) {};
+  TestGame(): MainClass(640,480), t1(0.0, 0.0, 0.5, 1.0, 1.0, 0.0), t2(1.0,0.0,1.5,1.0,2.0,0.0), t3(0.5,1.0,1.0,2.0,1.5,1.0) {
+    state.bright=true;
+    state.brightness=0.0;
+  };
   virtual ~TestGame();
   virtual auto stop() -> void;
 };

renderer/shapes/triangle.cpp

@@ -17,25 +17,14 @@ Triangle::Triangle(float ax, float ay, float bx, float by, float cx, float cy)
 }
 auto Triangle::init(GLfloat * colors, int size) -> void {
   GLfloat triangle_vertices[] = {
-    A.x, A.y,
-    B.x, B.y,
-    C.x, C.y
+    A.x, A.y, colors[0], colors[1], colors[2],
+    B.x, B.y, colors[3], colors[4], colors[5],
+    C.x, C.y, colors[6], colors[7], colors[8]
   };
   glGenBuffers(1, &vbo_triangle);
   glBindBuffer(GL_ARRAY_BUFFER, vbo_triangle); //Create VBO
   //Fill VBO
   glBufferData(GL_ARRAY_BUFFER, sizeof(triangle_vertices), triangle_vertices, GL_STATIC_DRAW);
-  
-  //Init colors
-  if(!colors)
-    useColors=false;
-  else {
-    useColors=true;
-    glGenBuffers(1, &vbo_triangle_colors);
-    glBindBuffer(GL_ARRAY_BUFFER, vbo_triangle_colors);
-    glBufferData(GL_ARRAY_BUFFER, size, colors, GL_STATIC_DRAW);
-    
-  }
 }
 Triangle::~Triangle()
 {
@@ -44,11 +33,30 @@ Triangle::~Triangle()
 bool Triangle::render(GLint attrib, GLint color_attrib)
 {
   glBindBuffer(GL_ARRAY_BUFFER, vbo_triangle);
-  glVertexAttribPointer(attrib, 2, GL_FLOAT, GL_FALSE, 0, 0);
-  if(useColors) {
-    glBindBuffer(GL_ARRAY_BUFFER, vbo_triangle_colors);
-    glVertexAttribPointer(color_attrib, 3, GL_FLOAT, GL_FALSE, 0, 0);
-  }
+  glVertexAttribPointer(attrib, 2, GL_FLOAT, GL_FALSE, 5*sizeof(GLfloat), 0);
+  glVertexAttribPointer(color_attrib, 3, GL_FLOAT, GL_FALSE, 5*sizeof(GLfloat), (GLvoid*) (2 * sizeof(GLfloat)));
   glDrawArrays(GL_TRIANGLES, 0, 3);
   return true;
 }
+auto Triangle::setPos(float ax, float ay, float bx, float by, float cx, float cy)  -> void
+{
+  A.x=ax-1.0;
+  A.y=ay-1.0;
+  B.x=bx-1.0;
+  B.y=by-1.0;
+  C.x=cx-1.0;
+  C.y=cy-1.0;
+}
+auto Triangle::update(GLfloat* colors, int size) -> void
+{
+  glDeleteBuffers(1, &vbo_triangle);
+  GLfloat triangle_vertices[] = {
+    A.x, A.y, colors[0], colors[1], colors[2],
+    B.x, B.y, colors[3], colors[4], colors[5],
+    C.x, C.y, colors[6], colors[7], colors[8]
+  };
+  glGenBuffers(1, &vbo_triangle);
+  glBindBuffer(GL_ARRAY_BUFFER, vbo_triangle); //Create VBO
+  //Fill VBO
+  glBufferData(GL_ARRAY_BUFFER, sizeof(triangle_vertices), triangle_vertices, GL_STATIC_DRAW);
+}

renderer/shapes/triangle.h

@@ -4,16 +4,17 @@
 #include <renderer/shapes/float2D.h>
 class Triangle {
 private:
-  GLuint vbo_triangle, vbo_triangle_colors;
+  GLuint vbo_triangle;
   float2D A;
   float2D B;
   float2D C; //The three points
-  bool useColors;
 public:
   Triangle(float x, float y, float alen, float blen, float clen);
   Triangle(float ax, float ay, float bx, float by, float cx, float cy);
   ~Triangle();
-  auto init(GLfloat * colors=nullptr, int size=0) -> void;
+  auto init(GLfloat * colors, int size) -> void;
   auto render(GLint attrib, GLint colorAttrib) -> bool;
+  auto setPos(float ax, float ay, float bx, float by, float cx, float cy) -> void;
+  auto update(GLfloat * colors, int size) -> void;
 };
 #endif

shaders/triangle.f.glsl

@@ -1,7 +1,15 @@
+#ifdef GL_ES
+# ifdef GL_FRAGMENT_PRECISION_HIGH
+    precision highp float;
+# else
+    precision mediump float;
+# endif
+#endif
 varying vec3 f_color;
+varying vec2 f_coord2d;
 void main(void) {
   gl_FragColor[0] = f_color[0];
   gl_FragColor[1] = f_color[1];
   gl_FragColor[2] = f_color[2];
-  gl_FragColor[3] = floor(mod(gl_FragCoord.y, 2.0));
+  gl_FragColor[3] = f_coord2d.y+1;
 }

shaders/triangle.v.glsl

@@ -1,7 +1,9 @@
 attribute vec2 coord2d;
 attribute vec3 v_color;
 varying vec3 f_color;
+varying vec2 f_coord2d;
 void main(void) {
   gl_Position = vec4(coord2d, 0.0, 1.0);
   f_color = v_color;
+  f_coord2d = coord2d;
 }

state.h

@@ -0,0 +1,7 @@
+#ifndef __STATE_H
+#define __STATE_H
+struct GameState {
+  bool bright;
+  float brightness;
+};
+#endif