Port handle_input and face_normal to assembly

Makefile

@@ -1,7 +1,7 @@
 # Build flat binary
 
-bin/mineassemble.bin: bin src/link.ld bin/init.o bin/interrupts.o bin/vga.o bin/main.o bin/reference.o bin/textures.o bin/cmath.o bin/splash.o bin/world.o bin/player.o bin/graphics.o bin/globals.o
-	ld -m elf_i386 -T src/link.ld -o bin/mineassemble.bin bin/init.o bin/interrupts.o bin/vga.o bin/main.o bin/reference.o bin/textures.o bin/cmath.o bin/splash.o bin/world.o bin/player.o bin/graphics.o bin/globals.o
+bin/mineassemble.bin: bin src/link.ld bin/init.o bin/interrupts.o bin/vga.o bin/main.o bin/reference.o bin/textures.o bin/cmath.o bin/splash.o bin/world.o bin/player.o bin/input.o bin/graphics.o bin/globals.o
+	ld -m elf_i386 -T src/link.ld -o bin/mineassemble.bin bin/init.o bin/interrupts.o bin/vga.o bin/main.o bin/reference.o bin/textures.o bin/cmath.o bin/splash.o bin/world.o bin/player.o bin/input.o bin/graphics.o bin/globals.o
 
 bin/reference.o: src/reference.c
 	gcc -m32 -c -g -o bin/reference.o src/reference.c -std=c99 -ffreestanding -Ofast

src/constants.asm

@@ -19,5 +19,32 @@
 ; Internal constants
 ;
 
+; Block types
 %define BLOCK_AIR 0
-%define BLOCK_DIRT 1
+%define BLOCK_DIRT 1
+
+; Block faces
+%define FACE_LEFT 0
+%define FACE_RIGHT 1
+%define FACE_BOTTOM 2
+%define FACE_TOP 3
+%define FACE_BACK 4
+%define FACE_FRONT 5
+
+; Key scancodes
+%define KEY_ESC 0x01
+
+%define KEY_Q 0x10
+%define KEY_E 0x12
+
+%define KEY_W 0x11
+%define KEY_A 0x1E
+%define KEY_S 0x1F
+%define KEY_D 0x20
+
+%define KEY_SPACE 0x39
+
+%define KEY_UP 0x48
+%define KEY_LEFT 0x4B
+%define KEY_RIGHT 0x4D
+%define KEY_DOWN 0x50

src/globals.asm

@@ -10,7 +10,7 @@
 
 global vga
 
-global zero, half_pi, nhalf_pi
+global zero, half_pi, neg_half_pi
 
 global hFov
 
@@ -23,7 +23,7 @@ section .data
         ; Helpful constants
         zero dd 0.0
         half_pi dd 1.57
-        nhalf_pi dd -1.57
+        neg_half_pi dd -1.57
 
         ; Horizontal field-of-view
         hFov dd HOR_FOV

src/graphics.asm

@@ -4,6 +4,9 @@
 
 [bits 32]
 
+global ray_dir, face_normal
+
+extern zero
 extern hFov
 extern yawC, yawS, pitchC, pitchS
 
@@ -15,134 +18,179 @@ section .data
         height dd 200
         halfHeight dd 100
         aspect dd 1.6
-        naspect dd -1.6
+        neg_aspect dd -1.6
         two dd 2.0
         half dd 0.5
         doubleCircle dd 720.0
 
 section .text
 
-    global rayDir
-
-    ; Takes screen space x and y and returns ray direction
-    ; as (x, y, z) floats
-rayDir:
-    push ebp
-    mov ebp, esp
-
-    ; Allocate local variables (vFov, fov, clipX, clipY, length)
-    sub esp, 20
-
-    ; Load struct address (x, y, z)
-    mov eax, dword [ebp + 8]
-
-    ; Calculate vertical fov and fov constant from horizontal fov
-
-    ; vFov = 2.0f * atanf(tanf(hFov / 720.0f * M_PI) * 320.0f / 200.0f);
-    ; RPN: 2.0 hFov 720.0 / pi * tan width * height / atan mul
-    fld dword [two]
-    fld dword [hFov]
-    fld dword [doubleCircle]
-    fdiv
-    fldpi
-    fmul
-    fptan
-    fstp dword [eax] ; Dump 1 the tan instruction pushes for some reason
-    fild dword [width]
-    fmul
-    fild dword [height]
-    fdiv
-    fld1 ; 1 required for atan (takes two parameters like atan2 in C)
-    fpatan
-    fmul
-    fst dword [ebp - 4] ; vFov
-
-    ; fov = tanf(0.5f * vFov);
-    ; RPN: 0.5 vFov * tan
-    fld dword [half]
-    fmul
-    fptan
-    fstp dword [eax]
-    fstp dword [ebp - 8] ; fov
-
-    ; clip X = x / 160.0f - 1.0f
-    ; RPN: x 160.0 / 1.0 -
-    fild dword [ebp + 12] ; x parameter
-    fild dword [halfWidth]
-    fdiv
-    fld1
-    fsub
-    fstp dword [ebp - 12] ; clipX
-
-    ; clip Y = 1.0f - y / 100.0f
-    ; RPN: 1.0 y 100.0 / -
-    fld1
-    fild dword [ebp + 16] ; y parameter
-    fild dword [halfHeight]
-    fdiv
-    fsub
-    fstp dword [ebp - 16] ; clipY
-
-    ; X dir = 1.6f * fov * yawC * clipX + fov * yawS * pitchS * clipY - pitchC * yawS
-    ; RPN: 1.6 fov yawC clipX * * * fov yawS pitchS clipY * * * + pitchC yawS * -
-    fld dword [aspect]
-    fld dword [ebp - 8] ; fov
-    fld dword [yawC]
-    fld dword [ebp - 12] ; clipX
-    fmul
-    fmul
-    fmul
-    fld dword [ebp - 8] ; fov
-    fld dword [yawS]
-    fld dword [pitchS]
-    fld dword [ebp - 16] ; clipY
-    fmul
-    fmul
-    fmul
-    fadd
-    fld dword [pitchC]
-    fld dword [yawS]
-    fmul
-    fsub
-    fstp dword [eax] ; X dir
-
-    ; Y dir = fov * pitchC * clipY + pitchS
-    ; RPN: fov pitchC clipY * * pitchS +
-    fld dword [ebp - 8] ; fov
-    fld dword [pitchC]
-    fld dword [ebp - 16] ; clipY
-    fmul
-    fmul
-    fld dword [pitchS]
-    fadd
-    fstp dword [eax + 4] ; Y dir
-
-    ; Z dir = -1.6f * fov * yawS * clipX + fov * yawC * pitchS * clipY - pitchC * yawC
-    ; RPN: naspect fov yawS clipX * * * fov yawC pitchS clipY * * * + pitchC yawC * -
-    fld dword [naspect]
-    fld dword [ebp - 8] ; fov
-    fld dword [yawS]
-    fld dword [ebp - 12] ; clipX
-    fmul
-    fmul
-    fmul
-    fld dword [ebp - 8] ; fov
-    fld dword [yawC]
-    fld dword [pitchS]
-    fld dword [ebp - 16] ; clipY
-    fmul
-    fmul
-    fmul
-    fadd
-    fld dword [pitchC]
-    fld dword [yawC]
-    fmul
-    fsub
-    fstp dword [eax + 8] ; Z dir
-
-    ; Resulting direction is not normalized, but that doesn't matter
-    ; for the raytracing algorithm
-
-    mov esp, ebp
-    pop ebp
-    ret 4
+        ; Takes screen space x and y and returns ray direction
+        ; as (x, y, z) floats
+    ray_dir:
+        push ebp
+        mov ebp, esp
+
+        ; Allocate local variables (vFov, fov, clipX, clipY, length)
+        sub esp, 20
+
+        ; Load struct address (x, y, z)
+        mov eax, dword [ebp + 8]
+
+        ; Calculate vertical fov and fov constant from horizontal fov
+
+        ; vFov = 2.0f * atanf(tanf(hFov / 720.0f * M_PI) * 320.0f / 200.0f);
+        ; RPN: 2.0 hFov 720.0 / pi * tan width * height / atan mul
+        fld dword [two]
+        fld dword [hFov]
+        fld dword [doubleCircle]
+        fdiv
+        fldpi
+        fmul
+        fptan
+        fstp dword [eax] ; Dump 1 the tan instruction pushes for some reason
+        fild dword [width]
+        fmul
+        fild dword [height]
+        fdiv
+        fld1 ; 1 required for atan (takes two parameters like atan2 in C)
+        fpatan
+        fmul
+        fst dword [ebp - 4] ; vFov
+
+        ; fov = tanf(0.5f * vFov);
+        ; RPN: 0.5 vFov * tan
+        fld dword [half]
+        fmul
+        fptan
+        fstp dword [eax]
+        fstp dword [ebp - 8] ; fov
+
+        ; clip X = x / 160.0f - 1.0f
+        ; RPN: x 160.0 / 1.0 -
+        fild dword [ebp + 12] ; x parameter
+        fild dword [halfWidth]
+        fdiv
+        fld1
+        fsub
+        fstp dword [ebp - 12] ; clipX
+
+        ; clip Y = 1.0f - y / 100.0f
+        ; RPN: 1.0 y 100.0 / -
+        fld1
+        fild dword [ebp + 16] ; y parameter
+        fild dword [halfHeight]
+        fdiv
+        fsub
+        fstp dword [ebp - 16] ; clipY
+
+        ; X dir = 1.6f * fov * yawC * clipX + fov * yawS * pitchS * clipY - pitchC * yawS
+        ; RPN: 1.6 fov yawC clipX * * * fov yawS pitchS clipY * * * + pitchC yawS * -
+        fld dword [aspect]
+        fld dword [ebp - 8] ; fov
+        fld dword [yawC]
+        fld dword [ebp - 12] ; clipX
+        fmul
+        fmul
+        fmul
+        fld dword [ebp - 8] ; fov
+        fld dword [yawS]
+        fld dword [pitchS]
+        fld dword [ebp - 16] ; clipY
+        fmul
+        fmul
+        fmul
+        fadd
+        fld dword [pitchC]
+        fld dword [yawS]
+        fmul
+        fsub
+        fstp dword [eax] ; X dir
+
+        ; Y dir = fov * pitchC * clipY + pitchS
+        ; RPN: fov pitchC clipY * * pitchS +
+        fld dword [ebp - 8] ; fov
+        fld dword [pitchC]
+        fld dword [ebp - 16] ; clipY
+        fmul
+        fmul
+        fld dword [pitchS]
+        fadd
+        fstp dword [eax + 4] ; Y dir
+
+        ; Z dir = -1.6f * fov * yawS * clipX + fov * yawC * pitchS * clipY - pitchC * yawC
+        ; RPN: neg_aspect fov yawS clipX * * * fov yawC pitchS clipY * * * + pitchC yawC * -
+        fld dword [neg_aspect]
+        fld dword [ebp - 8] ; fov
+        fld dword [yawS]
+        fld dword [ebp - 12] ; clipX
+        fmul
+        fmul
+        fmul
+        fld dword [ebp - 8] ; fov
+        fld dword [yawC]
+        fld dword [pitchS]
+        fld dword [ebp - 16] ; clipY
+        fmul
+        fmul
+        fmul
+        fadd
+        fld dword [pitchC]
+        fld dword [yawC]
+        fmul
+        fsub
+        fstp dword [eax + 8] ; Z dir
+
+        ; Resulting direction is not normalized, but that doesn't matter
+        ; for the raytracing algorithm
+
+        mov esp, ebp
+        pop ebp
+        ret 4
+
+    ; Returns normal of given block face (face, *nx, *ny, *nz)
+    face_normal:
+        ; Initialize nx, ny and nz to zero (no direction)
+        mov eax, [esp + 8] ; nx
+        mov dword [eax], 0
+        mov eax, [esp + 12] ; ny
+        mov dword [eax], 0
+        mov eax, [esp + 16] ; nz
+        mov dword [eax], 0
+
+        ; Jump to face
+        mov eax, [esp + 4]
+        jmp [.face_tbl + eax * 4]
+
+        ; Face jump table
+    .face_tbl:
+        dd .face_left
+        dd .face_right
+        dd .face_bottom
+        dd .face_top
+        dd .face_back
+        dd .face_front
+    .face_left:
+        mov eax, [esp + 8] ; nx = -1
+        mov dword [eax], -1
+        ret
+    .face_right:
+        mov eax, [esp + 8] ; nx = 1
+        mov dword [eax], 1
+        ret
+    .face_bottom:
+        mov eax, [esp + 12] ; ny = -1
+        mov dword [eax], -1
+        ret
+    .face_top
+        mov eax, [esp + 12] ; ny = 1
+        mov dword [eax], 1
+        ret
+    .face_back:
+        mov eax, [esp + 16] ; nz = -1
+        mov dword [eax], -1
+        ret
+    .face_front:
+        mov eax, [esp + 16] ; nz = 1
+        mov dword [eax], 1
+        ret