opengl_x11

commit 67612dc61659fa60a2b9579f377b5f8f8e78279f
parent 71eb5d10c9e4e0b1b1237534b1f82cca01a2b3e5
Author: bsandro <email@bsandro.tech>
Date:   Sun, 23 Nov 2025 12:43:39 +0200

Found how to render polygons displaying only triangles

Diffstat:
M
cube.c
 | 
6
+++++-
M
tesselating.c
 | 
1
+
M
trans.c
 | 
1
+

3 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/cube.c b/cube.c
@@ -249,7 +249,7 @@ int main(int argc, char *argv[]) {
     glGetProgramiv(shaderPrg, GL_LINK_STATUS, &prgStatus);
     printf("shader link status: %s\n", prgStatus == GL_TRUE ? "ok" : "error");
 
-    // texture
+    // texture - the only line that matters it seems!
     GLuint tex = mkTextureAstc(tex_fname);
     GLint position = glGetAttribLocation(shaderPrg, "position");
     glVertexAttribPointer(position, 3, GL_FLOAT, GL_FALSE, 5*sizeof(GLfloat), (void *)0);
@@ -317,9 +317,13 @@ int main(int argc, char *argv[]) {
         glUniformMatrix4fv(loc_projection, 1, GL_FALSE, projection[0]);
 
         glUseProgram(shaderPrg);
+        // if I remove next 3 lines the texture is still being rendered, curious
         glUniform1i(tex, 0);
         glActiveTexture(GL_TEXTURE0);
         glBindTexture(GL_TEXTURE_2D, tex);
+        // ultra useful debug
+        //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+
         for (int i=0; i<LEN(cubePositions); ++i) {
             mat4 model;
             glm_mat4_identity(model);
diff --git a/tesselating.c b/tesselating.c
@@ -218,6 +218,7 @@ int main(int argc, char *argv[]) {
         //printf("%f\n", fabsf(sinf(current_ts()-t_started)));
 
         glUseProgram(shaderPrg);
+        //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 
         GLuint list = glGenLists(1);
         glNewList(list, GL_COMPILE);
diff --git a/trans.c b/trans.c
@@ -285,6 +285,7 @@ int main(int argc, char *argv[]) {
         glUniformMatrix4fv(transform, 1, GL_FALSE, trans[0]);
 
         glUseProgram(shaderPrg);
+
         glUniform1i(tex, 0);
         glActiveTexture(GL_TEXTURE0);
         glBindTexture(GL_TEXTURE_2D, tex);