Merge pull request #75 from rust3ds/feat/lighting

[Feature] Lighting implementation

Author: Meziu

.gitignore

@@ -1,3 +1,6 @@
+# IDE files
+.zed
+
 # Generated by Cargo
 # will have compiled files and executables
 debug/

citro3d/Cargo.toml

@@ -16,6 +16,7 @@ ctru-rs = { git = "https://github.com/rust3ds/ctru-rs.git" }
 ctru-sys = { git = "https://github.com/rust3ds/ctru-rs.git" }
 document-features = "0.2.11"
 libc = "0.2.175"
+pin_array = "0.1.2"
 
 [features]
 default = ["glam"]

citro3d/examples/assets/frag-shader.pica

@@ -0,0 +1,74 @@
+; modified version of https://github.com/devkitPro/3ds-examples/blob/ea519187782397c279609da80310e0f8c7e80f09/graphics/gpu/fragment_light/source/vshader.v.pica
+; Example PICA200 vertex shader
+
+; Uniforms
+.fvec projection[4], modelView[4]
+
+; Constants
+.constf myconst(0.0, 1.0, -1.0, 0.5)
+.alias  zeros myconst.xxxx ; Vector full of zeros
+.alias  ones  myconst.yyyy ; Vector full of ones
+.alias  half  myconst.wwww
+
+; Outputs
+.out outpos position
+.out outtex texcoord0
+.out outclr color
+.out outview view
+.out outnq normalquat
+
+; Inputs (defined as aliases for convenience)
+.in inpos
+.in innrm
+.in intex
+
+.proc main
+	; Force the w component of inpos to be 1.0
+	mov r0.xyz, inpos
+	mov r0.w,   ones
+
+	; r1 = modelView * inpos
+	dp4 r1.x, modelView[0], r0
+	dp4 r1.y, modelView[1], r0
+	dp4 r1.z, modelView[2], r0
+	dp4 r1.w, modelView[3], r0
+
+	; outview = -r1
+	mov outview, -r1
+
+	; outpos = projection * r1
+	dp4 outpos.x, projection[0], r1
+	dp4 outpos.y, projection[1], r1
+	dp4 outpos.z, projection[2], r1
+	dp4 outpos.w, projection[3], r1
+
+	; outtex = intex
+	mov outtex, intex
+
+	; Transform the normal vector with the modelView matrix
+	; TODO: use a separate normal matrix that is the transpose of the inverse of modelView
+	dp3 r14.x, modelView[0], innrm
+	dp3 r14.y, modelView[1], innrm
+	dp3 r14.z, modelView[2], innrm
+	dp3 r6.x, r14, r14
+	rsq r6.x, r6.x
+	mul r14.xyz, r14.xyz, r6.x
+
+	mov r0, myconst.yxxx
+	add r4, ones, r14.z
+	mul r4, half, r4
+	cmp zeros, ge, ge, r4.x
+	rsq r4, r4.x
+	mul r5, half, r14
+	jmpc cmp.x, degenerate
+
+	rcp r0.z, r4.x
+	mul r0.xy, r5, r4
+
+degenerate:
+	mov outnq, r0
+	mov outclr, ones
+
+	; We're finished
+	end
+.end