opengl_x11

commit bed49138833a575a2588eeb2f5ef78a9b71eed1b
parent 646ba013c9b55efd0daebd002da96b2abea20300
Author: bsandro <email@bsandro.tech>
Date:   Sat,  8 Nov 2025 13:04:03 +0200

using ASTC texture (buggy version)

Diffstat:
M
texture.c
 | 
82
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---

1 file changed, 79 insertions(+), 3 deletions(-)
diff --git a/texture.c b/texture.c
@@ -14,6 +14,28 @@
 #define STB_IMAGE_IMPLEMENTATION
 #include "stb_image.h"
 
+#define GL_CHECK(x)                                                                           \
+x;                                                                                            \
+{                                                                                             \
+    GLenum glError = glGetError();                                                            \
+    if (glError!=GL_NO_ERROR) {                                                               \
+        printf("glGetError() = %i (%#.8x) at %s:%i\n", glError, glError, __FILE__, __LINE__); \
+        exit(EXIT_FAILURE);                                                                   \
+    }                                                                                         \
+}
+
+/* ASTC header declaration. */
+typedef struct
+{
+    uint8_t magic[4];
+    uint8_t blockdim_x;
+    uint8_t blockdim_y;
+    uint8_t blockdim_z;
+    uint8_t xsize[3];
+    uint8_t ysize[3];
+    uint8_t zsize[3];
+} astc_header;
+
 static const double current_ts() {
     struct timespec ts;
     timespec_get(&ts, TIME_UTC);
@@ -86,7 +108,7 @@ static GLuint mkTexture(const char *filename) {
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
     int w, h, numchan;
     stbi_set_flip_vertically_on_load(1);
-    unsigned char *data = stbi_load(filename, &w, &h, &numchan, 0);
+    uint8_t *data = stbi_load(filename, &w, &h, &numchan, 0);
     if (data) {
         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
         glGenerateMipmap(GL_TEXTURE_2D);
@@ -98,6 +120,52 @@ static GLuint mkTexture(const char *filename) {
     return tex;
 }
 
+static GLuint mkTextureAstc(const char *filename) {
+    FILE *f = fopen(filename, "rb");
+    if (f==NULL) {
+        printf("error loading file %s\n", filename);
+        exit(EXIT_FAILURE);
+    }
+
+    fseek(f, 0, SEEK_END);
+    int64_t fsize = ftell(f);
+    rewind(f);
+
+    uint8_t *data = malloc(fsize);
+    if (fread(data, 1, fsize, f) != fsize) {
+        printf("error reading file %s\n", filename);
+        exit(EXIT_FAILURE);
+    }
+
+    const astc_header *astc_data = (astc_header *)data;
+    /* Merge x,y,z-sizes from 3 chars into one integer value. */
+    GLsizei xsize = astc_data->xsize[0] + (astc_data->xsize[1] << 8) + (astc_data->xsize[2] << 16);
+    GLsizei ysize = astc_data->ysize[0] + (astc_data->ysize[1] << 8) + (astc_data->ysize[2] << 16);
+    GLsizei zsize = astc_data->zsize[0] + (astc_data->zsize[1] << 8) + (astc_data->zsize[2] << 16);
+
+    /* Compute number of blocks in each direction. */
+    GLsizei xblocks = (xsize + astc_data->blockdim_x - 1) / astc_data->blockdim_x;
+    GLsizei yblocks = (ysize + astc_data->blockdim_y - 1) / astc_data->blockdim_y;
+    GLsizei zblocks = (zsize + astc_data->blockdim_z - 1) / astc_data->blockdim_z;
+
+    GLsizei astc_size = xblocks * yblocks * zblocks << 4;
+
+    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_REPEAT));
+    GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT));
+    //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(glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGBA_ASTC_6x6_KHR, xsize, ysize, 0, astc_size, (const GLvoid *)astc_data));
+    //GL_CHECK(glGenerateMipmap(GL_TEXTURE_2D));
+    GL_CHECK(glEnable(GL_TEXTURE_2D));
+
+    fclose(f);
+    return tex;
+}
+
 void __attribute__((constructor)) start() {
     printf("start()\n");
     t_started = current_ts();
@@ -112,7 +180,6 @@ int main(int argc, char *argv[]) {
     XSetWindowAttributes swa;
     Window win;
     XWindowAttributes gwa;
-    XEvent xev;
     GLint attr[] = { GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER, None };
 
     if (dpy == NULL) {
@@ -139,6 +206,14 @@ int main(int argc, char *argv[]) {
     GLXContext ctx = glXCreateContext(dpy, vi, NULL, GL_TRUE);
     glXMakeCurrent(dpy, win, ctx);
 
+    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);
@@ -174,7 +249,8 @@ int main(int argc, char *argv[]) {
     printf("shader link status: %s\n", prgStatus == GL_TRUE ? "ok" : "error");
 
     // texture
-    GLuint tex = mkTexture("hina1.png");
+    //GLuint tex = mkTexture("hina.png");
+    GLuint tex = mkTextureAstc("hina.astc");
     GLint position = glGetAttribLocation(shaderPrg, "position");
     glVertexAttribPointer(position, 2, GL_FLOAT, GL_FALSE, 4*sizeof(GLfloat), (void *)0);
     glEnableVertexAttribArray(position);