using procedural generation to creat a disk but the texture does not work properly

Question

the desired result is for the texture to be pretty much the same throughout the disk however it seems to only render properly at a few triangle shaped areas round the edge

disk.cpp

void disk::disk(int sides)
{
    float interval = ( 2 * PI )/sides;
    float angle = 0.0f;
    groundtexture = SOIL_load_OGL_texture

    (
        "gfx/ground.png", 
        SOIL_LOAD_AUTO,
        SOIL_CREATE_NEW_ID,
        SOIL_FLAG_MIPMAPS | SOIL_FLAG_NTSC_SAFE_RGB | SOIL_FLAG_COMPRESS_TO_DXT
    );
    glBegin(GL_TRIANGLES);
    for (int i = 0; i < sides; i++)
    {
        glBindTexture(GL_TEXTURE_2D,groundtexture);
        glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
        glTexCoord2f(0.5, -0.5);
        glVertex3f(0, 0, 0);

        glTexCoord2f(cos(angle) / 2 + 0.5, - (sin(angle) / 2 + 0.5));
        glVertex3f(cos(angle), sin(angle), 0);

        glTexCoord2f(cos(angle + interval) / 2 + 0.5, -(sin(angle + interval) / 2 - 0.5));
        glVertex3f(cos(angle + interval), sin(angle + interval), 0);

        angle += interval;
    }
    glVertex3f(cos(0), sin(0), 0);
    glEnd();
    }

the disk does render but the texture does not render properly. with the edit suggested the disk does not texture right

You'll get OpenGL errors, anyway. `glBindTexture` respectively `glTexParameteri` is not allowed within `glBegin`/`glEnd` sequences. Bind the texture and set the texture parameters before `glBegin`! — Rabbid76, Dec 08 '19 at 21:46

Rabbid76 · Accepted Answer · 2019-12-08T22:32:40.417

You'll get OpenGL errors, anyway. glBindTexture, glTexParameteri, respectively glTexEnvf is not allowed within glBegin/glEnd sequences. Only instructions which modify the attributes or specify a vertex are allowed.
Bind the texture and set the texture parameters before glBegin:

glBindTexture(GL_TEXTURE_2D, myTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

glBegin(GL_TRIANGLES);
for (int i = 0; i < sides; i++)
{
    glTexCoord2f(0.5, -0.5);
    glVertex3f(0, 0, 0);

    glTexCoord2f(cos(angle) / 2 + 0.5, - (sin(angle) / 2 + 0.5));
    glVertex3f(cos(angle), sin(angle), 0);

    glTexCoord2f(cos(angle + interval) / 2 + 0.5, -(sin(angle + interval) / 2 - 0.5));
    glVertex3f(cos(angle + interval), sin(angle + interval), 0);

    angle += interval;
}
glEnd();

score 0 · Answer 2 · answered Dec 08 '19 at 18:25

0

GL_TEXTURE_MAG_FILTER cannot be GL_LINEAR_MIPMAP_LINEAR. It should be GL_LINEAR instead. So replace this line:

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR);

with

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

answered Dec 08 '19 at 18:25

SurvivalMachine

7,946
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57
87

now the texture still does not look right at all. looks a bit better tho so thanks – memelord420360 Dec 08 '19 at 18:33

score 0 · Answer 3 · answered Dec 09 '19 at 03:28

0

GL_MODULATE is an integer value, and not a float value. Use the correct method if you want correct results ;)

glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

answered Dec 09 '19 at 03:28

robthebloke

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using procedural generation to creat a disk but the texture does not work properly

3 Answers3