Support obj vertex colors

example/book.odin

@@ -3,21 +3,16 @@ package example
 
 import glm "core:math/linalg/glsl"
 import     "core:strings"
-import     "core:slice"
 import gl  "../wasm/webgl"
 import     "../obj"
 
 @private
 State_Book :: struct {
-	rotation:  mat4,
-	objects:    []Object,
-}
-
-Object :: struct {
 	using locations: Input_Locations_Boxes,
-	vao      : VAO,
+	vao:       VAO,
 	positions: []vec3,
-	colors   : []u8vec4,
+	colors:    []u8vec4,
+	rotation:  mat4,
 }
 
 @private
@@ -33,40 +28,30 @@ setup_book :: proc(s: ^State_Book, program: gl.Program) {
 		obj.parse_line(&data, line)
 	}
 
-	objects: [dynamic]Object
-
-	for object in data.objects {
-		append(&objects, Object{})
-		o := last(&objects)
-
-		o.vao = gl.CreateVertexArray()
+	s.vao = gl.CreateVertexArray()
 
-		lines := obj.object_to_triangles(data, object, context.allocator)
-
-		o.positions = lines.pos[:len(lines)]
-		o.colors    = lines.col[:len(lines)]
-
-		for &pos in o.positions {
-			pos *= 1000
-		}
-
-		slice.fill(o.colors, rand_color())
-
-
-		gl.BindVertexArray(o.vao)
+	vertices := obj.object_to_triangles(data, data.objects[0], context.allocator)
 
-		input_locations_boxes(&o.locations, program)
+	s.positions = vertices.pos[:len(vertices)]
+	for &pos in s.positions {
+		pos *= 1000
+	}
 
-		attribute(o.a_position, gl.CreateBuffer(), o.positions)
-		attribute(o.a_color   , gl.CreateBuffer(), o.colors)
+	s.colors = make([]rgba, len(vertices))
+	for &col, i in s.colors {
+		col = to_rgba(vertices[i].col)
 	}
 
-	s.objects = objects[:]
 
-	/* Init rotation */
-	s.rotation = 1
+	gl.BindVertexArray(s.vao)
+
+	input_locations_boxes(&s.locations, program)
 
+	attribute(s.a_position, gl.CreateBuffer(), s.positions)
+	attribute(s.a_color   , gl.CreateBuffer(), s.colors)
 
+	/* Init rotation */
+	s.rotation = 1
 }
 
 @private
@@ -89,15 +74,9 @@ frame_book :: proc(s: ^State_Book, delta: f32) {
 	mat *= glm.mat4Translate({0, 0, -900 + scale * 720})
 	mat *= s.rotation
 
-
-
-	for &o in s.objects {
-
-		gl.BindVertexArray(o.vao)
-
-		uniform(o.u_matrix, mat)
-
-		gl.DrawArrays(gl.TRIANGLES, 0, len(o.positions))
-	}
+	gl.BindVertexArray(s.vao)
 
+	uniform(s.u_matrix, mat)
+
+	gl.DrawArrays(gl.TRIANGLES, 0, len(s.positions))
 }

example/chair.odin

@@ -45,16 +45,14 @@ setup_chair :: proc(s: ^State_Chair, program: gl.Program) {
 		lines := obj.object_to_triangles(data, object, context.allocator)
 
 		o.positions = lines.pos[:len(lines)]
-		o.colors    = lines.col[:len(lines)]
-
 		for &pos in o.positions {
 			pos *= 100
 			pos.y -= 300
 		}
-
+
+		o.colors = make([]rgba, len(o.positions))
 		slice.fill(o.colors, rand_color())
 
-
 		gl.BindVertexArray(o.vao)
 
 		input_locations_boxes(&o.locations, program)

example/public/index.html

@@ -53,7 +53,7 @@ <h4 style="margin-bottom: 0.5rem;">Demos</h4>
 				<li><a href="#lathe">       Lathe       </a></li>
 				<li><a href="#suzanne">     Suzanne     </a></li>
 				<li><a href="#chair">       Chair       </a></li>
-				<!-- <li><a href="#book">        Book        </a></li> -->
+				<li><a href="#book">        Book        </a></li>
 			</ol>
 		</nav>
 

example/suzanne.odin

@@ -30,12 +30,11 @@ setup_suzanne :: proc(s: ^State_Suzanne, program: gl.Program) {
 	lines := obj.object_to_lines(data, data.objects[0], context.allocator)
 
 	s.positions = lines.pos[:len(lines)]
-	s.colors    = lines.col[:len(lines)]
-
 	for &pos in s.positions {
 		pos *= 100
 	}
 
+	s.colors = make([]rgba, len(s.positions))
 	slice.fill(s.colors, GREEN)
 
 	/* Init rotation */

example/utils.odin

@@ -69,11 +69,16 @@ u8vec4_to_vec4 :: #force_inline proc "contextless" (rgba: u8vec4) -> vec4 {
 	return {f32(rgba.r)/255, f32(rgba.g)/255, f32(rgba.b)/255, f32(rgba.a)/255}
 }
 rgba_to_vec4 :: u8vec4_to_vec4
+vec4_from_rgba :: rgba_to_vec4
 
 to_rgba_3_1 :: #force_inline proc "contextless" (color: $A/[3]u8, a: u8) -> rgba {
 	return {color.r, color.g, color.b, a}
 }
-to_rgba :: proc {to_rgba_3_1}
+vec3_to_rgba :: #force_inline proc "contextless" (v: vec3, a: u8 = 255) -> rgba {
+	return {u8(v.r*255), u8(v.g*255), u8(v.b*255), a}
+}
+to_rgba :: proc {to_rgba_3_1, vec3_to_rgba}
+
 
 last_array         :: #force_inline proc "contextless" (arr: $T/[$N]$E)       -> E  {return arr[len(arr)-1]}
 last_dyn_array     :: #force_inline proc "contextless" (arr: $T/[dynamic]$E)  -> E  {return arr[len(arr)-1]}

obj/parser.odin

@@ -17,9 +17,7 @@ u8vec4 :: [4]u8
 
 Index :: struct {
 	/* 
-	 indices start ar 1
-	 zero means it points to nowhere
-	 `data.positions[idx.position-1]`
+	 indices are base-1
 	*/
 	position: int,
 	texcoord: int,
@@ -99,9 +97,12 @@ Data :: struct {
 // }
 
 init_data :: proc (data: ^Data, allocator := context.allocator) {
-	data.positions  = make([dynamic]vec3,   0, 32, allocator)
-	data.texcoords  = make([dynamic]vec2,   0, 32, allocator)
-	data.normals    = make([dynamic]vec3,   0, 32, allocator)
+
+	// indices are base-1, add zero index to be able to index it normally
+	data.positions  = make([dynamic]vec3,   1, 32, allocator)
+	data.texcoords  = make([dynamic]vec2,   1, 32, allocator)
+	data.normals    = make([dynamic]vec3,   1, 32, allocator)
+
 	data.colors     = make([dynamic]vec3,   0, 32, allocator)
 	data.objects    = make([dynamic]Object, 1,  4, allocator)
 	data.objects[0] = object_make(data)
@@ -445,21 +446,21 @@ parse_line :: proc (data: ^Data, str: string)
 			parse_usemtl(data, &ptr)
 		}
 	}
-
-	// if len(data.colors) > 0 {
-	//     /* Fill the remaining slots in the colors array */
-	// 	for _ in 0 ..< len(data.positions) - len(data.colors) {
-	// 		append(&data.colors, 1)
-	// 	}
-	// }
 }
 
 Vertex :: struct {
 	pos: vec3,
-	col: u8vec4,
+	col: vec3,
 }
 Vertices :: #soa[]Vertex
 
+vertex_get_from_index :: proc (data: Data, idx: Index) -> (v: Vertex) {
+	v.pos = data.positions[idx.position]
+	// colors array is only filled if the colors data is in the file
+	v.col = data.colors[idx.position] if idx.position < len(data.colors) else 1
+	return
+}
+
 object_to_triangles :: proc (data: Data, g: Object, allocator := context.allocator) -> Vertices {
 
 	vertices := make(#soa[dynamic]Vertex, 0, 3*len(g.indices), allocator)
@@ -468,9 +469,9 @@ object_to_triangles :: proc (data: Data, g: Object, allocator := context.allocat
 		for i in 2 ..< len(indices) {
 			a, b, c := indices[0], indices[i-1], indices[i]
 			append(&vertices, ..[]Vertex{
-				{pos = data.positions[a.position-1]},
-				{pos = data.positions[b.position-1]},
-				{pos = data.positions[c.position-1]},
+				vertex_get_from_index(data, a),
+				vertex_get_from_index(data, b),
+				vertex_get_from_index(data, c),
 			})
 		}
 	}
@@ -486,12 +487,12 @@ object_to_lines :: proc (data: Data, g: Object, allocator := context.allocator)
 		for i in 2 ..< len(indices) {
 			a, b, c := indices[0], indices[i-1], indices[i]
 			append(&vertices, ..[]Vertex{
-				{pos = data.positions[a.position-1]},
-				{pos = data.positions[b.position-1]},
-				{pos = data.positions[b.position-1]},
-				{pos = data.positions[c.position-1]},
-				{pos = data.positions[c.position-1]},
-				{pos = data.positions[a.position-1]},
+				vertex_get_from_index(data, a),
+				vertex_get_from_index(data, b),
+				vertex_get_from_index(data, b),
+				vertex_get_from_index(data, c),
+				vertex_get_from_index(data, c),
+				vertex_get_from_index(data, a),
 			})
 		}
 	}