egutierrez
3008b56e76
- 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>
120 lines
3.4 KiB
C++
120 lines
3.4 KiB
C++
#define GL_GLEXT_PROTOTYPES
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#include <GL/gl.h>
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#include <GL/glext.h>
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#include "gfx/gl_shader.h"
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#include <cstdio>
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#include <cstring>
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#include <regex>
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#include <string>
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namespace fn::gfx {
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static const char* k_vert_src = R"glsl(
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#version 330 core
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const vec2 verts[6] = vec2[](
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vec2(-1,-1), vec2(1,-1), vec2(-1,1),
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vec2(1,-1), vec2(1,1), vec2(-1,1)
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);
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void main() { gl_Position = vec4(verts[gl_VertexID], 0.0, 1.0); }
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)glsl";
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static const char* k_frag_preamble =
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"#version 330 core\n"
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"out vec4 fragColor;\n"
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"uniform vec2 u_resolution;\n"
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"uniform float u_time;\n"
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"uniform vec2 u_mouse;\n";
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static int parse_err_line(const char* log) {
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// Try "ERROR: 0:<line>:" format
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std::regex re1(R"(ERROR:\s*\d+:(\d+):)");
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// Try "0(<line>)" format
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std::regex re2(R"(\d+\((\d+)\))");
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std::cmatch m;
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if (std::regex_search(log, m, re1)) {
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return std::stoi(m[1].str());
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}
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if (std::regex_search(log, m, re2)) {
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return std::stoi(m[1].str());
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}
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return -1;
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}
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static unsigned int compile_shader(GLenum type, const char** srcs, int count, std::string& out_err, int& out_line) {
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unsigned int s = glCreateShader(type);
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glShaderSource(s, count, srcs, nullptr);
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glCompileShader(s);
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GLint ok = 0;
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glGetShaderiv(s, GL_COMPILE_STATUS, &ok);
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if (!ok) {
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GLint len = 0;
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glGetShaderiv(s, GL_INFO_LOG_LENGTH, &len);
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out_err.resize(static_cast<size_t>(len));
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glGetShaderInfoLog(s, len, nullptr, &out_err[0]);
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out_line = parse_err_line(out_err.c_str());
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glDeleteShader(s);
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return 0;
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}
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return s;
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}
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CompileResult compile_fragment(const std::string& user_fragment_src) {
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CompileResult result;
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// Vertex shader (no preamble needed — it's a standalone complete shader)
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std::string vert_err;
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int vert_line = -1;
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unsigned int vert = compile_shader(GL_VERTEX_SHADER, &k_vert_src, 1, vert_err, vert_line);
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if (!vert) {
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result.err_msg = "vertex: " + vert_err;
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result.err_line = vert_line;
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return result;
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}
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// Fragment shader — prepend preamble, then user body
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const char* frag_srcs[2] = { k_frag_preamble, user_fragment_src.c_str() };
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std::string frag_err;
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int frag_line = -1;
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unsigned int frag = compile_shader(GL_FRAGMENT_SHADER, frag_srcs, 2, frag_err, frag_line);
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if (!frag) {
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glDeleteShader(vert);
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result.err_msg = frag_err;
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// Adjust line: subtract preamble lines (4 lines)
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if (frag_line > 4) result.err_line = frag_line - 4;
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else result.err_line = frag_line;
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return result;
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}
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// Link
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unsigned int prog = glCreateProgram();
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glAttachShader(prog, vert);
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glAttachShader(prog, frag);
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glLinkProgram(prog);
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glDeleteShader(vert);
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glDeleteShader(frag);
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GLint ok = 0;
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glGetProgramiv(prog, GL_LINK_STATUS, &ok);
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if (!ok) {
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GLint len = 0;
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glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &len);
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result.err_msg.resize(static_cast<size_t>(len));
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glGetProgramInfoLog(prog, len, nullptr, &result.err_msg[0]);
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result.err_line = parse_err_line(result.err_msg.c_str());
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glDeleteProgram(prog);
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return result;
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}
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result.program = prog;
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result.ok = true;
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return result;
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}
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void delete_program(unsigned int program) {
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if (program) glDeleteProgram(program);
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}
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} // namespace fn::gfx
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