Modern OpenGL

OpenGL Blending Filter

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OpenGL Blending Filter

14.OpenGLBlendingFilter.zip


 glEnable(GL_BLEND);
 if (g_filter == 0)                     // Default (no blending) = Cs*1
  glBlendFunc(GL_ONE, GL_ZERO);
 else if (g_filter == 1)                // Draw background only = Cd*1
  glBlendFunc(GL_ZERO, GL_ONE);
 else if (g_filter == 2)                // Cs*1 + Cd*1
  glBlendFunc(GL_ONE, GL_ONE);
 else if (g_filter == 3)                // Alpha blending (back-to-front) = Cs*As + Cd*(1-As)
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 else if (g_filter == 4)                // Additive blending (brighten the scene) = Cs*As + Cd*1
  glBlendFunc(GL_SRC_ALPHA, GL_ONE);
 else if (g_filter == 5)                // Multiplicative blending = Cd*Cs
  glBlendFunc(GL_ZERO, GL_SRC_COLOR);
 else if (g_filter == 6)                // darken the scene = Cd*As
  glBlendFunc(GL_ZERO, GL_SRC_ALPHA);
 else if (g_filter == 7)                 // Invert all the colors = Cs*(1-Cd)
  glBlendFunc(GL_ONE_MINUS_DST_COLOR, GL_ZERO);

Modern OpenGL

Texture Animation

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Texture Animation

13.OpenGLTextureShadedSquareAnimation.zip

// init 중간생략..

for (int i=0; i<7; i++)
{
char filename[255];
sprintf(filename, “tacgun0%d.rgb”, i);
texture[i] = InitTexture(filename);
}


// draw 중간생략..

glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture[currentTex]);
drawSquare();
glBindTexture(GL_TEXTURE_2D, 0);

// update

void update()
{
static int currentTime, deltaTime, prevTime = 0;
currentTime = glutGet(GLUT_ELAPSED_TIME);
deltaTime = currentTime – prevTime;
prevTime = currentTime;
currentTex = (GLuint) ((float)currentTime * 0.01) % 7;
glutPostRedisplay();
}