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 +1,115 @@
+#include "app_base.h"
+#include "imgui.h"
+
+#include "gfx/shader_canvas.h"
+#include "gfx/gl_shader.h"
+#include "core/fps_overlay.h"
+#include "seed_shaders.h"
+
+#include <chrono>
+#include <string>
+
+static fn::gfx::ShaderCanvas g_canvas;
+static std::string g_source = PLASMA;
+static std::string g_last_err;
+static int g_last_err_line = -1;
+static std::chrono::steady_clock::time_point g_last_edit;
+static bool g_dirty = true;
+
+static void try_compile() {
+    auto r = fn::gfx::compile_fragment(g_source);
+    if (r.ok) {
+        fn::gfx::canvas_set_program(g_canvas, r.program);
+        g_last_err.clear();
+        g_last_err_line = -1;
+    } else {
+        g_last_err = r.err_msg;
+        g_last_err_line = r.err_line;
+    }
+}
+
+static void mark_dirty() {
+    g_last_edit = std::chrono::steady_clock::now();
+    g_dirty = true;
+}
+
+static void load_preset(const char* src) {
+    g_source = src;
+    mark_dirty();
+}
+
+static void render() {
+    if (!g_canvas.initialized) fn::gfx::canvas_init(g_canvas);
+
+    if (g_dirty) {
+        auto now = std::chrono::steady_clock::now();
+        auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(now - g_last_edit).count();
+        if (elapsed > 250) {
+            try_compile();
+            g_dirty = false;
+        }
+    }
+
+    ImGui::DockSpaceOverViewport(0, ImGui::GetMainViewport());
+
+    // --- Code panel ---
+    if (ImGui::Begin("Code")) {
+        if (ImGui::Button("Plasma"))  { load_preset(PLASMA); }
+        ImGui::SameLine();
+        if (ImGui::Button("Circle"))  { load_preset(CIRCLE); }
+        ImGui::SameLine();
+        if (ImGui::Button("Checker")) { load_preset(CHECKER); }
+
+        ImVec2 avail = ImGui::GetContentRegionAvail();
+        float footer_height = g_last_err.empty() ? 0.0f : ImGui::GetTextLineHeightWithSpacing() + 8.0f;
+        ImVec2 editor_size(avail.x, avail.y - footer_height);
+
+        char buf[1 << 16];
+        size_t copy_len = g_source.size() < sizeof(buf) - 1 ? g_source.size() : sizeof(buf) - 1;
+        memcpy(buf, g_source.c_str(), copy_len);
+        buf[copy_len] = '\0';
+
+        ImGui::PushFont(nullptr); // use default monospace-ish font
+        if (ImGui::InputTextMultiline("##code", buf, sizeof(buf), editor_size,
+                                      ImGuiInputTextFlags_AllowTabInput)) {
+            g_source = buf;
+            mark_dirty();
+        }
+        ImGui::PopFont();
+
+        if (!g_last_err.empty()) {
+            ImGui::Separator();
+            if (g_last_err_line > 0) {
+                ImGui::TextColored(ImVec4(1, 0.4f, 0.4f, 1), "line %d: %s",
+                                   g_last_err_line, g_last_err.c_str());
+            } else {
+                ImGui::TextColored(ImVec4(1, 0.4f, 0.4f, 1), "%s", g_last_err.c_str());
+            }
+        }
+    }
+    ImGui::End();
+
+    // --- Canvas panel ---
+    if (ImGui::Begin("Canvas")) {
+        fn::gfx::canvas_render(g_canvas, static_cast<float>(ImGui::GetTime()));
+    }
+    ImGui::End();
+
+    // --- Controls panel ---
+    if (ImGui::Begin("Controls")) {
+        ImGui::TextDisabled("Controls (fase 2)");
+        ImGui::Spacing();
+        fps_overlay();
+    }
+    ImGui::End();
+}
+
+int main() {
+    fn::AppConfig cfg;
+    cfg.title  = "shaders_lab";
+    cfg.width  = 1400;
+    cfg.height = 860;
+    int rc = fn::run_app(cfg, render);
+    fn::gfx::canvas_destroy(g_canvas);
+    return rc;
+}