twn_lines.c: 3d case

apps/demos/scenery/scenes/ingame.c

@@ -32,7 +32,7 @@ static void process_fly_mode(State *state) {
     scn->looking_direction = dir_and_up.direction;
 
     const Vec3 right = m_vec_norm(m_vec_cross(dir_and_up.direction, dir_and_up.up));
-    const float speed = 0.04f; /* TODO: put this in a better place */
+    const float speed = 0.1f; /* TODO: put this in a better place */
     if (input_action_pressed("player_left"))
         scn->pos = vec3_sub(scn->pos, m_vec_scale(right, speed));
 

include/twn_draw.h

@@ -47,6 +47,13 @@ TWN_API void draw_line(Vec2 start,
                        float thickness, /* optional, default: 1 */
                        Color color);    /* optional, default: all 255 */
 
+/* intended for debugging and spatial reference */
+TWN_API void draw_line_3d(Vec3 start,
+                          Vec3 finish,
+                          float thickness, /* optional, default: 1 */
+                          Color color);    /* optional, default: all 255 */
+
+
 /* TODO: combine with draw_rectangle()? */
 TWN_API void draw_box(Rect rect,
                       float thickness,  /* optional, default: 1 */

src/rendering/twn_draw.c

@@ -56,6 +56,9 @@ void render_clear(void) {
 
     for (size_t i = 0; i < hmlenu(ctx.quad_batches); ++i)
         arrsetlen(ctx.quad_batches[i].value.primitives, 0);
+
+    for (size_t i = 0; i < hmlenu(ctx.line_batches); ++i)
+        arrsetlen(ctx.line_batches[i].value.vertices, 0);
 }
 
 
@@ -328,7 +331,7 @@ static void render_2d(void) {
                 render_circle(&invocation.primitive->circle);
                 break;
             case PRIMITIVE_2D_LINES:
-                render_lines(&invocation.primitive->line);
+                render_lines(&invocation.primitive->line, false);
                 stbds_arrfreef(invocation.primitive->line.vertices);
                 break;
             case PRIMITIVE_2D_TEXT:
@@ -361,7 +364,7 @@ static void render_2d(void) {
                 render_text(&invocation.primitive->text);
                 break;
             case PRIMITIVE_2D_LINES:
-                render_lines(&invocation.primitive->line);
+                render_lines(&invocation.primitive->line, false);
                 break;
             default:
                 SDL_assert(false);
@@ -388,6 +391,9 @@ static void render_space(void) {
     for (size_t i = 0; i < hmlenu(ctx.billboard_batches); ++i)
         finally_draw_billboard_batch(&ctx.billboard_batches[i].value, ctx.billboard_batches[i].key);
 
+    for (size_t i = 0; i < hmlenu(ctx.line_batches); ++i)
+        render_lines(&ctx.line_batches[i].value, true);
+
     render_skybox(); /* after everything else, as to use depth buffer for early z rejection */
 }
 

src/rendering/twn_draw_c.h

@@ -322,7 +322,7 @@ IndexBuffer get_circle_element_buffer(void);
 
 void render_circle(const CirclePrimitive *circle);
 
-void render_lines(const LinePrimitive *line);
+void render_lines(const LinePrimitive *line, bool is_3d);
 
 void render_rectangle(const RectPrimitive *rectangle);
 

src/rendering/twn_lines.c

@@ -14,6 +14,11 @@ void draw_line(Vec2 start,
     if (fabsf(1.0f - thickness) >= 0.00001f)
         log_warn("Thickness isn't yet implemented for line drawing (got %f)", (double)thickness);
 
+    if (thickness < 1.0f) {
+        log_warn("Invalid thickness given.");
+        return;
+    }
+
     struct LineVertex const v0 = { .position = (Vec3){start.x, start.y, 0}, .color = color };
     struct LineVertex const v1 = { .position = (Vec3){finish.x, finish.y, 0}, .color = color };
 
@@ -46,7 +51,36 @@ void draw_line(Vec2 start,
 }
 
 
-void render_lines(LinePrimitive const *line) {
+void draw_line_3d(Vec3 start,
+                  Vec3 finish,
+                  float thickness,
+                  Color color)
+{
+    if (fabsf(1.0f - thickness) >= 0.00001f)
+        log_warn("Thickness isn't yet implemented for line drawing (got %f)", (double)thickness);
+
+    if (thickness < 1.0f) {
+        log_warn("Invalid thickness given.");
+        return;
+    }
+
+    struct LineVertex const v0 = { .position = start, .color = color };
+    struct LineVertex const v1 = { .position = finish, .color = color };
+
+    /* 3d case, unordered depth based draw */
+    struct LineBatchItemKey const key = { .color = color, .thickness = (uint8_t)(floorf(thickness)) };
+    struct LineBatchItem *batch_p = hmgetp_null(ctx.line_batches, key);
+    if (!batch_p) {
+        hmput(ctx.line_batches, key, ((struct LinePrimitive){.thickness = thickness, .color = color}));
+        batch_p = &ctx.line_batches[hmlenu(ctx.line_batches) - 1];
+    }
+    arrput(batch_p->value.vertices, v0);
+    arrput(batch_p->value.vertices, v1);
+    return;
+}
+
+
+void render_lines(LinePrimitive const *line, bool is_3d) {
     DeferredCommandDraw command = {0};
 
     VertexBuffer buffer = get_scratch_vertex_array();
@@ -71,7 +105,9 @@ void render_lines(LinePrimitive const *line) {
     command.primitive_count = (uint32_t)arrlenu(line->vertices);
 
     command.geometry_mode = DEFERRED_COMMAND_DRAW_GEOMETRY_MODE_LINES;
-    command.pipeline = PIPELINE_2D;
+    command.pipeline = is_3d ? PIPELINE_SPACE : PIPELINE_2D;
+
+    command.texture_mode = line->color.a == 255 ? TEXTURE_MODE_OPAQUE : TEXTURE_MODE_GHOSTLY;
 
     command.depth_range_high = depth_range_high;
     command.depth_range_low = depth_range_low;

src/twn_engine_context_c.h

@@ -50,6 +50,13 @@ typedef struct EngineContext {
     MeshBatchItem *uncolored_mesh_batches;
     MeshBatchItem *billboard_batches;
     MeshBatchItem *quad_batches;
+    struct LineBatchItem {
+        struct LineBatchItemKey {
+            Color color;
+            uint8_t thickness;
+        } key;
+        struct LinePrimitive value;
+    } *line_batches;
     TextCache text_cache;
     TextureCache texture_cache;