How to animate 2D textures ?

OpenGL OpenGL: Basic Coding
1

Hello,
i want to make a very simple water effect without blending yet,
so i have a 2D square with a water texture mapped on it.
i have tried to move glTexCoord2f parameters
(at first i just want to animate the Y coordinates)
i want the wather to move from the top of my quad from the bottom and to make a circular movement (i’m not sure it’s a very clear explaination…)

here’s what i am tried :
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.
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GLfloat ycdeb=0.0f;
GLfloat ycfin=4.0f;
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glBegin(GL_QUADS);
glTexCoord2f(0.0f, ycdeb);glVertex3f(-20.0,0.0,0.0);
glTexCoord2f(0.0f, ycfin);glVertex3f(-20.0,0.0,-50.0);
glTexCoord2f(4.0f, ycfin);glVertex3f(20.0,0.0,-50.0);
glTexCoord2f(4.0f, ycdeb);glVertex3f(20.0,0.0,0.0);
glEnd();
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.
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if (g_keys->keyDown [VK_F5] == TRUE) // Is F1 Being Pressed?
{
if (ycfin==4.0)
{
ycfin=0.1f;
ycdeb+=0.001f;
}
if (ycdeb==4.0)
{
ycdeb=0.1f;
ycfin+=0.001f;
}

      ycfin+=0.001f;
	  ycdeb+=0.001f;
}

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.
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the circular effets seem to be good but the texture is not looking good, like if it was extensed.

if you can help me with this, tanks by advance.
Marsu

2

Hi there

use the texture matrix
ie

glBindTexture(GL_TEXTURE_2D,texid);
glMatrixMode(GL_TEXTURE_MATRIX); - i think this is the one
glTranslatef(x,y,z);
glMatrixMode(GL_MODELVIEW_MATRIX);

(its something like this ive got the code
at home and will check it tonight).

you can also rotate the texture using this
method.

Hope it helps

Mark.

3

tanks for help,i havn’t tried your code yet, but the idea of rotating a texture easily sounds good !

yesterday, i have take again a look at my code, i have put // behind my reset code (that was supposed to reset the UV coords to their starting value when they have reached the end value (4 in my example because 4 tiles)
and it works fine, but now i dont understand why,
i just increment the coords from 0 to ???, and from 4 to ???, it never ends, why didn’t the texture don’t move away from the poly, all works well and i don’t understand why, maybe if i let the programm run a while it will crash ? i havn’t tried.
Can you explain why ?
Marsu

4

how about if you try to include the sphere environment mapping inside the code just to make the water texture looks more real.
use texture generation modes.

5

ok, tanks for suggest this .
yet i just want the texture to move, after i will work on appearence :slight_smile:

Marsu