added textures for the hardware renderer

- removed "using" directive in .hpp
- reverse order of arguments for quaternion rotation, i.e. q.rot(v)
  instead of v.rot(q), where q is a quaterinon and v a vector
- pass the inverse of the view matrix to render_and_present_frame, to
  allow light calculation in shaders (we used to just pass the matrix of
  the quaternion of the transformation, i.e. discard scaling and
  translations)
- added another mesh and texture (viking_room) for testing purposes
- added transparent background option
- added Quaternion::look_towards(), which is the equivalent of
  Matrix4::look_at() but only for rotations
- various improvement to .obj parsing
- load texture coordinates from .obj file
- merged duplicate vertices in Mesh::linearize_indices()

1 files changed, 18 insertions, 16 deletions

diff --git a/src/shaders/shader.slang b/src/shaders/shader.slang
index e92f5aa..245df4b 100644
--- a/src/shaders/shader.slang
+++ b/src/shaders/shader.slang
@@ -1,12 +1,11 @@
 struct VertexInput {
     float3 pos;
     float3 normal;
+    float2 uv;
 };
 
 struct UniformBuffer {
-    float4x4 model, view, proj;
-    float4x4 camera_rot;
-    float3 camera_loc;
+    float4x4 model, view, proj, inv_view;
 };
 
 ConstantBuffer<UniformBuffer> ubo;
@@ -15,6 +14,7 @@ struct VertexOutput {
     float4 pos : SV_Position;
     float3 world_loc;
     float3 normal;
+    float2 uv;
 };
 
 [shader("vertex")]
@@ -23,7 +23,8 @@ VertexOutput vert_main(VertexInput vi) {
     float4 world_loc = mul(ubo.model, float4(vi.pos, 1.));
     vo.pos = mul(ubo.proj, mul(ubo.view, world_loc));
     vo.world_loc = world_loc.xyz;
-    vo.normal = vi.normal;
+    vo.normal = mul(ubo.model, float4(vi.normal, 0.)).xyz;
+    vo.uv = vi.uv;
     return vo;
 }
 
@@ -31,16 +32,17 @@ Sampler2D texture;
 
 [shader("fragment")]
 float4 frag_main(VertexOutput vo) : SV_Target {
-    float3 u = vo.world_loc - ubo.camera_loc;
-    float u_len_sq = dot(u, u);
-    u = normalize(u);
-    float attenuation = dot(mul(ubo.camera_rot, float4(0., 0., -1., 0.)).xyz, u);
-    if (attenuation < .7) attenuation = 0.f;
-    else if (attenuation > .8) attenuation = 1.;
-    else attenuation = (attenuation - .7) / .1;
-    float light = -dot(vo.normal, u) / u_len_sq;
-    if (light < 0.) light = 0.;
-    float final_light = .003 + light * attenuation * .8 * .997;
-    if (final_light > 1.) final_light = 1.;
-    return float4(final_light, final_light, final_light, 1.);
+    // float3 u = vo.world_loc - (ubo.inv_view * float4(0., 0., 0., 1.)).xyz;
+    // float u_len_sq = dot(u, u);
+    // u = normalize(u);
+    // float attenuation = dot(mul(ubo.inv_view, float4(0., 0., -1., 0.)).xyz, u);
+    // if (attenuation < .7) attenuation = 0.f;
+    // else if (attenuation > .8) attenuation = 1.;
+    // else attenuation = (attenuation - .7) / .1;
+    // float light = -dot(vo.normal, u) / u_len_sq;
+    // if (light < 0.) light = 0.;
+    // float final_light = .003 + light * attenuation * .8 * .997;
+    // if (final_light > 1.) final_light = 1.;
+    // return float4(final_light, final_light, final_light, 1.);
+    return float4(texture.Sample(vo.uv).rgb, 1.f);
 }