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>
This commit is contained in:
2026-04-24 20:32:14 +02:00
parent 5546ce6453
commit 042bb43b37
16 changed files with 823 additions and 0 deletions
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add_imgui_app(shaders_lab
main.cpp
${CMAKE_SOURCE_DIR}/functions/gfx/gl_shader.cpp
${CMAKE_SOURCE_DIR}/functions/gfx/gl_framebuffer.cpp
${CMAKE_SOURCE_DIR}/functions/gfx/fullscreen_quad.cpp
${CMAKE_SOURCE_DIR}/functions/gfx/shader_canvas.cpp
${CMAKE_SOURCE_DIR}/functions/core/fps_overlay.cpp
)
target_include_directories(shaders_lab PRIVATE
${CMAKE_CURRENT_SOURCE_DIR}
)
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#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;
}
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#pragma once
// GLSL 330 fragment shader bodies (no #version, no out, no uniform declarations).
// compile_fragment() prepends those automatically.
static const char* PLASMA = R"glsl(
void main() {
vec2 uv = gl_FragCoord.xy / u_resolution;
float t = u_time * 0.5;
float v1 = sin(uv.x * 10.0 + t);
float v2 = sin(uv.y * 10.0 + t * 1.3);
float v3 = sin((uv.x + uv.y) * 10.0 + t * 0.7);
float v4 = sin(length(uv - 0.5) * 20.0 - t * 2.0);
float v = (v1 + v2 + v3 + v4) * 0.25;
vec3 col = vec3(
sin(v * 3.14159 + 0.0) * 0.5 + 0.5,
sin(v * 3.14159 + 2.094) * 0.5 + 0.5,
sin(v * 3.14159 + 4.188) * 0.5 + 0.5
);
fragColor = vec4(col, 1.0);
}
)glsl";
static const char* CIRCLE = R"glsl(
void main() {
vec2 uv = gl_FragCoord.xy / u_resolution;
vec2 center = vec2(0.5);
float t = u_time;
// Animated center
center += vec2(sin(t * 0.7), cos(t * 0.5)) * 0.2;
float d = length(uv - center);
// Concentric rings
float rings = sin(d * 40.0 - t * 3.0) * 0.5 + 0.5;
// Radial glow
float glow = exp(-d * 4.0);
vec3 col = mix(
vec3(0.05, 0.1, 0.3),
vec3(0.2, 0.7, 1.0),
rings * glow + glow * 0.4
);
fragColor = vec4(col, 1.0);
}
)glsl";
static const char* CHECKER = R"glsl(
void main() {
vec2 uv = gl_FragCoord.xy / u_resolution;
float t = u_time;
// Animated scale and rotation
float scale = 8.0 + sin(t * 0.4) * 3.0;
float angle = t * 0.2;
float ca = cos(angle), sa = sin(angle);
vec2 p = uv - 0.5;
p = vec2(ca * p.x - sa * p.y, sa * p.x + ca * p.y);
p = p * scale + 0.5;
vec2 cell = floor(p);
float checker = mod(cell.x + cell.y, 2.0);
// Color gradient per cell
float hue = fract((cell.x + cell.y) * 0.1 + t * 0.05);
vec3 col_a = vec3(hue, 0.7, 0.9);
vec3 col_b = vec3(fract(hue + 0.5), 0.5, 0.7);
// Simple HSV to RGB
vec3 col = mix(col_b, col_a, checker);
// hue is already [0,1], apply saturation/value manually
float h = col.x * 6.0;
int i = int(h);
float f = h - float(i);
float p2 = col.z * (1.0 - col.y);
float q2 = col.z * (1.0 - col.y * f);
float t2 = col.z * (1.0 - col.y * (1.0 - f));
vec3 rgb;
if (i == 0) rgb = vec3(col.z, t2, p2);
else if (i == 1) rgb = vec3(q2, col.z, p2);
else if (i == 2) rgb = vec3(p2, col.z, t2);
else if (i == 3) rgb = vec3(p2, q2, col.z);
else if (i == 4) rgb = vec3(t2, p2, col.z);
else rgb = vec3(col.z, p2, q2);
fragColor = vec4(rgb, 1.0);
}
)glsl";