🔒 Locked

Problem with multitexturing and vertex array

Started by Sting Jan 21, 2004 at 4:55 PM 11 replies 1.5k views

Original Post

Jan 21, 2004 at 4:55 PM

I render a terrain (heightmap) with a vertex array and i use multitexturing for the terain texture (terrain tex and detail tex). The terrain look great but the problem i have is that any other texture (not multitexturing) show the terrain texture. (ex: the skybox show a blending of the skybox texture and the terrain texture) If i do not render the terrain, the other texture work fine. here is the code i use to render my terrain: glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glClientActiveTextureARB(GL_TEXTURE0_ARB); glTexCoordPointer(2, GL_FLOAT, 0, texture_array); glActiveTextureARB(GL_TEXTURE0_ARB); glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D, texture[TERRAIN_TEX].texID); glClientActiveTextureARB(GL_TEXTURE1_ARB); glTexCoordPointer(2, GL_FLOAT, 0, texture_array); glActiveTextureARB(GL_TEXTURE1_ARB); glEnable(GL_TEXTURE_2D); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB); glTexEnvi(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 2); glBindTexture(GL_TEXTURE_2D, texture[TERRAIN_DETAIL].texID); glMatrixMode(GL_TEXTURE); glLoadIdentity(); glScalef(detail, detail, 1); glMatrixMode(GL_MODELVIEW); glVertexPointer(3, GL_FLOAT, 0, vertex_array); glDrawArrays(GL_TRIANGLE_STRIP, 0, nb_vertex); glDisableClientState(GL_TEXTURE_COORD_ARRAY); glDisableClientState(GL_VERTEX_ARRAY); to render the other texture (ex: skybox) glBindTexture(GL_TEXTURE_2D, texture[BACK_ID].texID); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glBegin(GL_QUADS); glTexCoord2f(1.0f, 0.0f); glVertex3f(x + width, y, z); glTexCoord2f(1.0f, 1.0f); glVertex3f(x + width, y + height, z); glTexCoord2f(0.0f, 1.0f); glVertex3f(x, y + height, z); glTexCoord2f(0.0f, 0.0f); glVertex3f(x, y, z); glEnd(); ... (sorry for my english)

Ostsol

Jan 21, 2004 at 5:43 PM

Hmm. . . After you''ve set the texcoords and textures for your terrain, make sure to set glClientActiveTexture and glActiveTexture back to GL_TEXTURE0_ARB.

Sting

Author

Sting

Jan 21, 2004 at 5:59 PM

i tried and changed my code like this

glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);

glClientActiveTextureARB(GL_TEXTURE0_ARB);
glTexCoordPointer(2, GL_FLOAT, 0, texture_array);
glActiveTextureARB(GL_TEXTURE0_ARB);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texture[TERRAIN_TEX].texID);

glClientActiveTextureARB(GL_TEXTURE1_ARB);
glTexCoordPointer(2, GL_FLOAT, 0, texture_array);
glActiveTextureARB(GL_TEXTURE1_ARB);
glEnable(GL_TEXTURE_2D);

glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
glTexEnvi(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 2);

glBindTexture(GL_TEXTURE_2D, texture[TERRAIN_DETAIL].texID);

glMatrixMode(GL_TEXTURE);
glLoadIdentity();
glScalef(detail, detail, 1);
glMatrixMode(GL_MODELVIEW);

glVertexPointer(3, GL_FLOAT, 0, vertex_array);
glDrawArrays(GL_TRIANGLE_STRIP, 0, nb_vertex);

glClientActiveTextureARB(GL_TEXTURE0_ARB);
glActiveTextureARB(GL_TEXTURE0_ARB);

glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);

nom, the normale texture are fine but the mukltitexturing don''t work: i see the terrain texture but not the detail texture

Ostsol

Jan 21, 2004 at 6:14 PM

Try changing the glTexEnv code to this:

glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
glTexEnvi (GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_MODULATE);
glTexEnvi (GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 2);

glTexEnvi (GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE);
glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);

glTexEnvi (GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB);
glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR);

What you''re doing just seems to scale the colours of the detail texture, but not specify what texture combining operation to use.

Hope this helps. . .

Myopic Rhino

452

Myopic Rhino

Jan 21, 2004 at 6:17 PM

You need to call glEnableClientState(GL_TEXTURE_COORD_ARRAY) and glDisableClientState(GL_TEXTURE_COORD_ARRAY) for each texture unit. What''s happening is that the first time through the code, texture unit 0 is active, so you enable it. By the time you hit disable, texture unit 1 is active, so it''s the one that gets deactivated - texture unit 0 still has tex coord arrays enabled. The second and every other time through the code, texture unit 1 is the one that''s active on entry, so you enable it, and then it gets disabled at the end of the code. I think that''s what causing your problem.

Brother Bob

Mod

218

Brother Bob

Jan 21, 2004 at 6:19 PM

You need to enable/disable the texture coordinate array for each client side texture unit.


glClientActiveTextureARB(GL_TEXTURE0_ARB);
glTexCoordPointer(2, GL_FLOAT, 0, texture_array);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);

glClientActiveTextureARB(GL_TEXTURE1_ARB);
glTexCoordPointer(2, GL_FLOAT, 0, texture_array);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);

Bobby-D

Jan 22, 2004 at 2:25 AM

Use glDisable(GL_TEXTURE_2D) once you''ve finnished using multitexturing, to disable the TextureUnits you''re not using. Then set the active texture unit back to TextureUnit0. ie

glActiveTextureARB(GL_TEXTURE2_ARB);
glDisable(GL_TEXTURE_2D);
glActiveTextureARB(GL_TEXTURE1_ARB);
glDisable(GL_TEXTURE_2D);
glActiveTextureARB(GL_TEXTURE0_ARB);
...etc.

Sting

Author

Sting

Jan 22, 2004 at 3:34 AM

now it works, thank you all for your help

here is my code nom

glClientActiveTextureARB(GL_TEXTURE0_ARB);
glTexCoordPointer(2, GL_FLOAT, 0, texture_array);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glActiveTextureARB(GL_TEXTURE0_ARB);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texture[TERRAIN_TEX].texID);

glClientActiveTextureARB(GL_TEXTURE1_ARB);
glTexCoordPointer(2, GL_FLOAT, 0, texture_array);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glActiveTextureARB(GL_TEXTURE1_ARB);
glEnable(GL_TEXTURE_2D);

glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
glTexEnvi(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 2);

glBindTexture(GL_TEXTURE_2D, texture[TERRAIN_DETAIL].texID);

glMatrixMode(GL_TEXTURE);
glLoadIdentity();
glScalef(detail, detail, 1);
glMatrixMode(GL_MODELVIEW);

glVertexPointer(3, GL_FLOAT, 0, vertex_array);
glDrawArrays(GL_TRIANGLE_STRIP, 0, nb_vertex);

glActiveTextureARB(GL_TEXTURE1_ARB);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);

glActiveTextureARB(GL_TEXTURE0_ARB);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);

Brother Bob

Mod

218

Brother Bob

Jan 22, 2004 at 4:07 AM

You don''t have to enable/disable the vertex array for each texture unit. Only the texture coordinate array.

Sting

Author

Sting

Jan 22, 2004 at 8:00 AM

the other texture are ok but now i have a little other problem: the other texture are a little darker. If i change "detail" from my code

glMatrixMode(GL_TEXTURE);
glLoadIdentity();
glScalef(detail, detail, 1);
glMatrixMode(GL_MODELVIEW);

the brithness of all other texture change. detail=16 is the darker.

Sting

Author

Sting

Jan 26, 2004 at 10:46 AM

any idea?

Fingers_

Jan 26, 2004 at 3:37 PM

What Bobby-D said... You have to turn off the other texture unit if you don''t want the detail texture on the skybox.


glActiveTextureARB(GL_TEXTURE1_ARB);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);
glDisable(GL_TEXTURE_2D);

Sting

Author

Sting

Jan 26, 2004 at 4:56 PM

thank you, it''s working fine now.

Topic Locked

This topic has been locked by a moderator. New replies are not allowed.