Draw first triangle

include/rasteriser/rasteriser.h

@@ -13,6 +13,14 @@ typedef struct {
   vec2i_t p1;
 } line_t;
 
+typedef struct {
+  vec2i_t p0;
+  vec2i_t p1;
+  vec2i_t p2;
+} triangle_t;
+
+void draw_wireframe_triangle(window_t *wnd, triangle_t triangle,
+                             colour_t colour);
 void draw_line(window_t *wnd, line_t line, colour_t colour);
 
 #endif // !RASTERISER_H

src/rasteriser/main.c

@@ -23,23 +23,12 @@ int main(void) {
   // i32 h_min = ((i32)window.half_height) * -1;
   // i32 h_max = (i32)window.half_height;
 
-  line_t lines[] = {
+  triangle_t triangle = {
-      (line_t){
+      .p0 = {-200, -250},
-          (vec2i_t){.x = -300, .y = 0},
+      .p1 = {200, 50},
-          (vec2i_t){.x = 300, .y = 250},
+      .p2 = {20, 250},
-      },
-      (line_t){
-          (vec2i_t){.x = -200, .y = -100},
-          (vec2i_t){.x = 240, .y = 120},
-      },
-      (line_t){
-          (vec2i_t){.x = -50, .y = -200},
-          (vec2i_t){.x = 60, .y = 240},
-      },
   };
 
-  u32 count = ARR_LEN(lines);
-
   while (running) {
     while (SDL_PollEvent(&event)) {
       switch (event.type) {
@@ -51,9 +40,8 @@ int main(void) {
 
     clear_window(&window, bg);
 
-    for (u32 i = 0; i < count; ++i) {
+    draw_wireframe_triangle(&window, triangle,
-      draw_line(&window, lines[i], (colour_t){.colour = 0xffffffff});
+                            (colour_t){.colour = 0xffffffff});
-    }
 
     swap_buffers(&window);
   }

src/rasteriser/rasteriser.c

@@ -9,19 +9,26 @@
 
 internal list_float_t *interpolate(i32 i0, f32 d0, i32 i1, f32 d1);
 
+void draw_wireframe_triangle(window_t *wnd, triangle_t triangle,
+                             colour_t colour) {
+  draw_line(wnd, (line_t){triangle.p0, triangle.p1}, colour);
+  draw_line(wnd, (line_t){triangle.p1, triangle.p2}, colour);
+  draw_line(wnd, (line_t){triangle.p2, triangle.p0}, colour);
+}
+
 void draw_line(window_t *wnd, line_t line, colour_t colour) {
+  list_float_t *values = NULL;
+
+  if (abs(line.p1.x - line.p0.x) > abs(line.p1.y - line.p0.y)) {
+    if (line.p1.x < line.p0.x) {
+      vec_swap(vec2i_t, line.p0, line.p1);
+    }
+
     i32 x0 = line.p0.x;
     i32 y0 = line.p0.y;
     i32 x1 = line.p1.x;
     i32 y1 = line.p1.y;
 
-  list_float_t *values = NULL;
-
-  if (abs(x1 - x0) > abs(y1 - y0)) {
-    if (line.p1.x < line.p0.x) {
-      vec_swap(vec2i_t, line.p0, line.p1);
-    }
-
     values = interpolate(x0, y0, x1, y1);
     if (!values) {
       return;
@@ -35,6 +42,11 @@ void draw_line(window_t *wnd, line_t line, colour_t colour) {
       vec_swap(vec2i_t, line.p0, line.p1);
     }
 
+    i32 x0 = line.p0.x;
+    i32 y0 = line.p0.y;
+    i32 x1 = line.p1.x;
+    i32 y1 = line.p1.y;
+
     values = interpolate(y0, x0, y1, x1);
     if (!values) {
       return;