feat(shaders_lab): scaffold C++ app with GLSL live-reload canvas

- cpp/functions/gfx: gl_shader, gl_framebuffer, fullscreen_quad, shader_canvas - cpp/apps/shaders_lab: main + 3 seed shaders (plasma, circle, checker) - ImGui docking layout: Code | Canvas | Controls Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-04-24 20:32:14 +02:00
parent 5546ce6453
commit 042bb43b37
16 changed files with 823 additions and 0 deletions
@@ -0,0 +1,49 @@
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glext.h>
+
+#include "gfx/gl_framebuffer.h"
+
+namespace fn::gfx {
+
+static void create_tex(Framebuffer& f) {
+    glGenTextures(1, &f.tex);
+    glBindTexture(GL_TEXTURE_2D, f.tex);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, f.width, f.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    glBindTexture(GL_TEXTURE_2D, 0);
+}
+
+void fb_init(Framebuffer& f) {
+    f.width = 1;
+    f.height = 1;
+    create_tex(f);
+    glGenFramebuffers(1, &f.fbo);
+    glBindFramebuffer(GL_FRAMEBUFFER, f.fbo);
+    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, f.tex, 0);
+    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+}
+
+void fb_resize(Framebuffer& f, int w, int h) {
+    if (w == f.width && h == f.height) return;
+    f.width = w;
+    f.height = h;
+    if (f.tex) glDeleteTextures(1, &f.tex);
+    f.tex = 0;
+    create_tex(f);
+    glBindFramebuffer(GL_FRAMEBUFFER, f.fbo);
+    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, f.tex, 0);
+    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+}
+
+void fb_destroy(Framebuffer& f) {
+    if (f.fbo) { glDeleteFramebuffers(1, &f.fbo); f.fbo = 0; }
+    if (f.tex) { glDeleteTextures(1, &f.tex); f.tex = 0; }
+    f.width = 0;
+    f.height = 0;
+}
+
+} // namespace fn::gfx