opengl_x11

commit f50e8a885327cfe783ecc0593222c212dca160a3
parent 3c40752cea5fe396bdfb46eb32a8ca1dda78050c
Author: bsandro <email@bsandro.tech>
Date:   Mon, 10 Nov 2025 23:28:23 +0200

Loading texture from command line argument

Diffstat:
M
texture.c
 | 
41
+++++++++++++++++++++++++++++------------

1 file changed, 29 insertions(+), 12 deletions(-)
diff --git a/texture.c b/texture.c
@@ -24,6 +24,9 @@ x;                                                                              
     }                                                                                         \
 }
 
+#define ASTC_EXT ".astc"
+#define ASTC_LEN 5
+
 /* ASTC header declaration. */
 typedef struct
 {
@@ -107,9 +110,10 @@ static GLuint mkTexture(const char *filename) {
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
     int w, h, numchan;
-    stbi_set_flip_vertically_on_load(1);
-    uint8_t *data = stbi_load(filename, &w, &h, &numchan, 0);
+    //stbi_set_flip_vertically_on_load(1);
+    uint8_t *data = stbi_load(filename, &w, &h, &numchan, 3);
     if (data) {
+        printf("texture %dx%d %dbpp\n", w, h, numchan*8);
         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
         glGenerateMipmap(GL_TEXTURE_2D);
         glEnable(GL_TEXTURE_2D);
@@ -184,11 +188,11 @@ static GLuint mkTextureAstc(const char *filename) {
     GLuint tex;
     GL_CHECK(glGenTextures(1, &tex));
     GL_CHECK(glBindTexture(GL_TEXTURE_2D, tex));
-    //GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE));
-    //GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE));
+    GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)); // GL_REPEAT
+    GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)); // GL_CLAMP_TO_EDGE
     //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
-    GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
-    GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
+    GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST));
+    GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST));
     GL_CHECK(glCompressedTexImage2D(GL_TEXTURE_2D, 0, astc_format, xsize, ysize, 0, astc_size, (const GLvoid *)astc_data));
     //GL_CHECK(glGenerateMipmap(GL_TEXTURE_2D));
     GL_CHECK(glEnable(GL_TEXTURE_2D));
@@ -208,6 +212,19 @@ void __attribute((destructor)) end() {
 }
 
 int main(int argc, char *argv[]) {
+    const char *tex_fname;
+    bool is_astc = false;
+    if (argc>1) {
+        tex_fname = argv[1];
+        int len = strlen(tex_fname);
+        // ".astc" extension = 5 bytes
+        is_astc = (len>ASTC_LEN&&strncmp(tex_fname+len-ASTC_LEN, ASTC_EXT, ASTC_LEN)==0);
+    } else {
+        tex_fname = "hina.astc";
+        is_astc = true;
+    }
+    printf("texture file: %s (%s)\n", tex_fname, is_astc ? "astc" : "plain");
+
     Display *dpy = XOpenDisplay(NULL);
     XSetWindowAttributes swa;
     Window win;
@@ -238,20 +255,21 @@ int main(int argc, char *argv[]) {
     GLXContext ctx = glXCreateContext(dpy, vi, NULL, GL_TRUE);
     glXMakeCurrent(dpy, win, ctx);
 
-    GLint extn;
+    // USEFUL DEBUG INFO
+    //@todo validate ASTC support
+    /*GLint extn;
     GL_CHECK(glGetIntegerv(GL_NUM_EXTENSIONS, &extn));
     printf("%d GL Extensions:\n", extn);
     for (GLint i=0; i<extn; ++i) {
         printf("\t%s\n", glGetStringi(GL_EXTENSIONS, i));
-    }
-
+    }*/
 
     GLuint vao;
     glGenVertexArrays(1, &vao);
     glBindVertexArray(vao);
 
     // @todo geh
-    const GLfloat c = 0.099f;
+    const GLfloat c = 0; //0.099f;
 
     // x,y,tx,ty
     static const GLfloat vertices[] = {
@@ -284,8 +302,7 @@ int main(int argc, char *argv[]) {
     printf("shader link status: %s\n", prgStatus == GL_TRUE ? "ok" : "error");
 
     // texture
-    //GLuint tex = mkTexture("hina.png");
-    GLuint tex = mkTextureAstc("hina.astc");
+    GLuint tex = is_astc ? mkTextureAstc(tex_fname) : mkTexture(tex_fname);
     GLint position = glGetAttribLocation(shaderPrg, "position");
     glVertexAttribPointer(position, 2, GL_FLOAT, GL_FALSE, 4*sizeof(GLfloat), (void *)0);
     glEnableVertexAttribArray(position);