Frox/Vektor
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feat: stroke tessellation and gpu rendering

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This commit is contained in:
Froxwin
2026-03-07 01:07:17 +05:30
parent b1ae584469
commit a1abe76dbd
7 changed files with 218 additions and 49 deletions
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147
src/ui/vektorcanvas.c
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@@ -2,30 +2,34 @@
#include "gtk/gtk.h"
#include "../core/raster.h"
#include "src/core/primitives.h"
#include "uicontroller.h"
#include "vektorcanvas.h"
#include <epoxy/gl_generated.h>
#define VKTR_CANVAS_WIDTH 400
#define VKTR_CANVAS_HEIGHT 400
#define VKTR_CANVAS_SIZE (VKTR_CANVAS_WIDTH * VKTR_CANVAS_HEIGHT * 4)
char* read_file(const char* path) {
FILE* f = fopen(path, "rb");
if (!f)
return NULL;
fseek(f, 0, SEEK_END);
long size = ftell(f);
fseek(f, 0, SEEK_SET);
char* buffer = malloc(size + 1);
fread(buffer, 1, size, f);
buffer[size] = '\0'; // null-terminate
fclose(f);
return buffer;
}
static GLuint shader_program;
static GLuint vao;
static const char* vertex_shader_src =
"#version 300 es\n" // <- ES version
"layout(location = 0) in vec2 aPos;\n"
"void main() {\n"
" gl_Position = vec4(aPos, 0.0, 1.0);\n"
"}\n";
static const char* fragment_shader_src =
"#version 300 es\n" // <- ES version
"precision mediump float;\n" // required in ES for fragment color
"out vec4 FragColor;\n"
"void main() {\n"
" FragColor = vec4(1.0, 0.0, 0.0, 1.0);\n"
"}\n";
VertexBuffer vb;
static GLuint compile_shader(GLenum type, const char* src) {
GLuint shader = glCreateShader(type);
@@ -43,8 +47,17 @@ static GLuint compile_shader(GLenum type, const char* src) {
}
static void init_shader(void) {
GLuint vertex = compile_shader(GL_VERTEX_SHADER, vertex_shader_src);
GLuint fragment = compile_shader(GL_FRAGMENT_SHADER, fragment_shader_src);
char* vert_src = read_file("./shaders/triangle.vert.glsl");
char* frag_src = read_file("./shaders/triangle.frag.glsl");
if (!vert_src || !frag_src)
g_error("Failed to load shader files");
GLuint vertex = compile_shader(GL_VERTEX_SHADER, vert_src);
GLuint fragment = compile_shader(GL_FRAGMENT_SHADER, frag_src);
printf("%s\n", vert_src);
printf("%s\n", frag_src);
shader_program = glCreateProgram();
glAttachShader(shader_program, vertex);
@@ -64,55 +77,113 @@ static void init_shader(void) {
}
static void init_geometry(void) {
// Vertices for a rectangle in NDC coordinates
float vertices[] = {
-0.5f, -0.5f, // bottom-left
0.5f, -0.5f, // bottom-right
0.5f, 0.5f, // top-right
-0.5f, 0.5f // top-left
};
unsigned int indices[] = {0, 1, 2, 2, 3, 0};
// V2 vs[3] = {(V2){-0.5, -0.5}, (V2){0.5, -0.5}, (V2){0.0, 0.5}};
// VertexBuffer vb =
// (VertexBuffer){.count = 3, .capacity = 3, .vertices = &vs[0]};
GLuint vbo, ebo;
VektorPolygon triangle = *vektor_polygon_new();
vektor_polygon_add_point(&triangle, (V2){-0.5f, -0.5f}); // bottom-left
vektor_polygon_add_point(&triangle, (V2){0.5f, -0.5f}); // bottom-right
vektor_polygon_add_point(&triangle, (V2){0.0f, 0.5f}); // top-center
VektorPrimitiveBuffer prims = {0};
vektor_primitivebuffer_add_primitive(
&prims,
(VektorPrimitive){.kind = VEKTOR_POLYGON, .polygon = &triangle});
vb = vektor_rasterize(&prims);
for (size_t i = 0; i < vb.count; i++) {
printf("Vertex %zu: x=%f, y=%f\n", i, vb.vertices[i].x,
vb.vertices[i].y);
}
GLuint vbo;
// 1. Create VAO
glGenVertexArrays(1, &vao);
glGenBuffers(1, &vbo);
glGenBuffers(1, &ebo);
glBindVertexArray(vao);
// 2. Create VBO
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices,
// 3. Upload your vertices (V2 = 2 floats per vertex)
glBufferData(GL_ARRAY_BUFFER, vb.count * sizeof(V2), vb.vertices,
GL_STATIC_DRAW);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float),
(void*)0);
// 4. Tell GL about the vertex layout
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, // layout location 0 in shader
2, // 2 components per vertex (x, y)
GL_FLOAT, // type
GL_FALSE, // do not normalize
sizeof(V2), // stride (size of one vertex)
(void*)0 // offset
);
glBindVertexArray(0);
}
static gboolean render(GtkGLArea* area, GdkGLContext* context) {
glUseProgram(shader_program);
GLuint uProjectionLoc = glGetUniformLocation(shader_program, "uProjection");
GLuint uColorLoc = glGetUniformLocation(shader_program, "uColor");
float projectionMatrix[16] = {1, 0, 0, 0, 0, 1, 0, 0,
0, 0, 1, 0, 0, 0, 0, 1};
glUniformMatrix4fv(uProjectionLoc, 1, GL_FALSE, projectionMatrix);
glUniform4f(uColorLoc, 1.0, 0.0, 1.0, 1.0); // magenta
glBindVertexArray(vao);
glDisable(GL_CULL_FACE);
// glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(shader_program);
glBindVertexArray(vao);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glDrawArrays(GL_TRIANGLES, 0, vb.count);
GLenum err = glGetError();
printf("OpenGL error: %x\n", err);
// glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
glUseProgram(0);
return TRUE;
}
static void dump_gl_info(GtkGLArea* area) {
gtk_gl_area_make_current(area);
if (gtk_gl_area_get_error(area)) {
g_warning("Failed to make GL context current");
return;
}
const GLubyte* renderer = glGetString(GL_RENDERER);
const GLubyte* vendor = glGetString(GL_VENDOR);
const GLubyte* version = glGetString(GL_VERSION);
const GLubyte* shading = glGetString(GL_SHADING_LANGUAGE_VERSION);
g_debug("GL Vendor : %s", vendor);
g_debug("GL Renderer : %s", renderer);
g_debug("GL Version : %s", version);
g_debug("GLSL Version : %s", shading);
GLint n;
glGetIntegerv(GL_NUM_EXTENSIONS, &n);
g_debug("Supported extensions (%d):", n);
for (GLint i = 0; i < n; ++i) {
g_debug(" %s", glGetStringi(GL_EXTENSIONS, i));
}
}
static void realize(GtkGLArea* area, gpointer user_data) {
gtk_gl_area_make_current(area);
if (gtk_gl_area_get_error(area) != NULL)
return; // context creation failed
glEnable(GL_DEBUG_OUTPUT);
dump_gl_info(area);
init_shader();
init_geometry();
}