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cube/source/main.c

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// SPDX-License-Identifier: CC0-1.0
//
// SPDX-FileContributor: Antonio Niño Díaz, 2022
#include <stdint.h>
#include <stdlib.h>
#define GBA_SCREEN_W 240
#define GBA_SCREEN_H 160
#define REG_DISPCNT *((volatile uint16_t *)0x04000000)
#define REG_KEYINPUT *((volatile uint16_t *)0x04000130)
#define DEFAULT_REG_KEYINPUT *((volatile uint16_t *)0x04000130)
#define KEY_DOWN_NOW(key) (~(REG_KEYINPUT) & key)
#define KEY_A 1
#define KEY_B 2
#define KEY_SELECT 3
#define KEY_START 4
#define KEY_DPAD_RIGHT 5
#define KEY_DPAD_LEFT 6
#define KEY_DPAD_UP 7
#define KEY_DPAD_DOWN 8
#define KEY_TRIGGER_LEFT 9
#define KEY_TRIGGER_RIGHT 10
#define DISPCNT_BG_MODE_MASK (0x7)
#define DISPCNT_BG_MODE(n) ((n) & DISPCNT_BG_MODE_MASK) // 0 to 5
#define DISPCNT_BG2_ENABLE (1 << 10)
#define MEM_VRAM_MODE4 ((uint8_t *)buffer)
#define SHOW_BACK 0x10;
#define FRONT_BUFFER (0x6000000)
#define BACK_BUFFER (0x600A000)
#define PALETTE ((uint16_t *)0x5000000)
static volatile uint8_t lastPaletteIndex = 0;
#define FIXED_POINT int32_t
#define FP 12
#define SHIFT_THRESHOLD 0.05
#define SHIFT_THRESHOLD_FP ((1 << FP) * SHIFT_THRESHOLD)
#define FLOAT2FIXED(value) (int)((value) * (1 << FP))
#define FIXED2FLOAT(value) ((value) / (float)(1 << FP))
static uint8_t *buffer = (uint8_t *)FRONT_BUFFER;
static inline uint16_t
RGB15(uint16_t r, uint16_t g, uint16_t b)
{
return (r & 0x1F) | ((g & 0x1F) << 5) | ((b & 0x1F) << 10);
}
void
flipBuffers()
{
if(buffer == (uint8_t *)FRONT_BUFFER) {
REG_DISPCNT &= ~SHOW_BACK;
buffer = (uint8_t *)BACK_BUFFER;
} else {
REG_DISPCNT |= SHOW_BACK;
buffer = (uint8_t *)FRONT_BUFFER;
}
}
///////////////////////////////////////////////////////////
#include <math.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <float.h>
#define CUBE_WIDTH 10
#define CUBE_WIDTH_FP ((1 << FP) * CUBE_WIDTH)
enum faces {
FACE_FRONT = 0,
FACE_LEFT,
FACE_RIGHT,
FACE_BOTTOM,
FACE_TOP,
FACE_BACK,
NUM_FACES,
};
#define STEP 20
#define STEP_FP ((1 << FP) * STEP)
#define ACTION_STEP 0.1
#define ACTION_STEP_FP ((1 << FP) * ACTION_STEP)
#define SCALE 5 // how much is our initial render scaled
#define K1 (20)
#define K2 (2 * CUBE_WIDTH + 10)
#define MULT_FP(a, b) ((a * b) >> FP)
#define SQ(n) (n * n)
#define SQ_FP(n) (MULT_FP(n, n))
#define GET_ROTATE_X_Q(a) ({ float _a = (a) ; \
struct Quaternions q = {}; q.w = FLOAT2FIXED(cos(_a * .5)); \
q.x = FLOAT2FIXED(sin(_a * .5)); q; })
#define GET_ROTATE_Y_Q(a) ({ float _a = (a) ; \
struct Quaternions q = {}; q.w = FLOAT2FIXED(cos(_a * .5)); \
q.y = FLOAT2FIXED(sin(_a * .5)); q; })
#define GET_ROTATE_Z_Q(a) ({ float _a = (a) ; \
struct Quaternions q = {}; q.w = FLOAT2FIXED(cos(_a * .5)); \
q.z = FLOAT2FIXED(sin(_a * .5)); q; })
//TODO Idle animations
#define IS_IDLE (Idle.x || Idle.y || Idle.z)
#define RESET_IDLE {Idle.x = 0; Idle.y = 0; Idle.z = 0;}
void
init_colors()
{
const uint16_t color_order[NUM_FACES + 1] = {
RGB15(0, 0, 0),
RGB15(31, 0, 0),
RGB15(0, 31, 0),
RGB15(0, 0, 31),
RGB15(0, 31, 31),
RGB15(31, 31, 0),
RGB15(31, 0, 31),
};
for ( ; lastPaletteIndex <= NUM_FACES ; ++lastPaletteIndex)
PALETTE[lastPaletteIndex] = color_order[lastPaletteIndex];
}
uint8_t
chooseColor(uint8_t c)
{
if (c >= 0 && c < NUM_FACES)
return c + 1; // palette 0 is bg
else
return 0;
}
void
putPx(uint16_t x, uint16_t y, uint8_t c)
{
for (uint8_t i = 0 ; i < SCALE ; ++i)
for (uint8_t j = 0 ; j < SCALE ; ++j) {
uint16_t pos = GBA_SCREEN_W * (y * SCALE + j) + x * SCALE + i;
buffer[pos] = chooseColor(c);
}
}
struct {
uint8_t x;
uint8_t y;
uint8_t z;
} Idle;
struct Quaternions {
FIXED_POINT w;
FIXED_POINT x;
FIXED_POINT y;
FIXED_POINT z;
} Target, Current;
static FIXED_POINT interpolationStep = 0;
static volatile uint16_t vertices[NUM_FACES * 2 * 4];
static volatile FIXED_POINT zBuffer[NUM_FACES * 2];
static volatile uint8_t shouldBreak = 1;
static volatile uint8_t currentlyMoving = 0;
static volatile uint8_t currentCountR = 0;
static volatile uint8_t frontFacingFace = FACE_FRONT;
void
normalize(struct Quaternions *q)
{
float n = sqrt(FIXED2FLOAT(SQ_FP(q->w) + SQ_FP(q->x) +
SQ_FP(q->y) + SQ_FP(q->z)));
if (n == 0.|| n == 1.)
return;
q->w = FLOAT2FIXED(FIXED2FLOAT(q->w) / n);
q->x = FLOAT2FIXED(FIXED2FLOAT(q->x) / n);
q->y = FLOAT2FIXED(FIXED2FLOAT(q->y) / n);
q->z = FLOAT2FIXED(FIXED2FLOAT(q->z) / n);
}
struct Quaternions
mult(struct Quaternions *q, FIXED_POINT x, FIXED_POINT y, FIXED_POINT z)
{
//p = q * p * qbar
struct Quaternions res;
// << 1 <=> * 2
res.w = 0;
res.x = MULT_FP(x, (SQ_FP(q->w) + SQ_FP(q->x) - SQ_FP(q->y) - SQ_FP(q->z)))
+ (MULT_FP(y, (MULT_FP(q->x, q->y) - MULT_FP(q->w, q->z))) << 1)
+ (MULT_FP(z, (MULT_FP(q->x, q->z) + MULT_FP(q->w, q->y))) << 1);
res.y = (MULT_FP(x, (MULT_FP(q->x, q->y) + MULT_FP(q->w,q->z))) << 1)
+ (MULT_FP(y, (SQ_FP(q->w) - SQ_FP(q->x) + SQ_FP(q->y) - SQ_FP(q->z))))
+ (MULT_FP(z, (MULT_FP(q->y, q->z) - MULT_FP(q->w, q->x))) << 1);
res.z = (MULT_FP(x, (MULT_FP(q->x, q->z) - MULT_FP(q->w, q->y))) << 1)
+ (MULT_FP(y, (MULT_FP(q->y, q->z) + MULT_FP(q->w, q->x))) << 1)
+ MULT_FP(z, (SQ_FP(q->w) - SQ_FP(q->x) - SQ_FP(q->y) + SQ_FP(q->z)));
return res;
}
// res in quat p
void
multQ(struct Quaternions *p, struct Quaternions *q)
{
if (p->x <= SHIFT_THRESHOLD_FP && p->x >= -SHIFT_THRESHOLD_FP
&& p->y <= SHIFT_THRESHOLD_FP && p->y >= -SHIFT_THRESHOLD_FP
&& p->z <= SHIFT_THRESHOLD_FP && p->z >= -SHIFT_THRESHOLD_FP) {
p = q;
return;
}
if (q->x <= SHIFT_THRESHOLD_FP && q->x >= -SHIFT_THRESHOLD_FP
&& q->y <= SHIFT_THRESHOLD_FP && q->y >= -SHIFT_THRESHOLD_FP
&& q->z <= SHIFT_THRESHOLD_FP && q->z >= -SHIFT_THRESHOLD_FP)
return;
FIXED_POINT w = MULT_FP(p->w, q->w) - MULT_FP(p->x, q->x) -
MULT_FP(p->y, q->y) - MULT_FP(p->z, q->z);
FIXED_POINT x = MULT_FP(p->w, q->x) + MULT_FP(p->x, q->w) +
MULT_FP(p->y, q->z) - MULT_FP(p->z, q->y);
FIXED_POINT y = MULT_FP(p->w, q->y) - MULT_FP(p->x, q->z) +
MULT_FP(p->y, q->w) + MULT_FP(p->z, q->x);
FIXED_POINT z = MULT_FP(p->w, q->z) + MULT_FP(p->x, q->y) -
MULT_FP(p->y, q->x) + MULT_FP(p->z, q->w);
p->w = w;
p->x = x;
p->y = y;
p->z = z;
}
uint8_t
chooseMainFace()
{
// TODO
return 0;
}
uint8_t
isInQuad(const uint16_t x, const uint16_t y, uint8_t current_face)
{
uint16_t *points = (uint16_t *)&vertices[current_face * 8];
uint8_t pos = 0, neg = 0;
int32_t d;
for (uint8_t i = 0; i < 4; ++i) {
if (points[2 * i] == x && points[2 * i + 1] == y)
return 1;
//Form a segment between the i'th point
uint16_t x1 = points[2 * i];
uint16_t y1 = points[2 * i + 1];
//And the i+1'th, or if i is the last, with the first point
uint8_t i2 = (i + 1) % 4;
uint16_t x2 = points[2 * i2];
uint16_t y2 = points[2 * i2 + 1];
//Compute the cross product
d = (x - x1) * (y2 - y1) - (y - y1) * (x2 - x1);
if (d > 0) ++pos;
if (d < 0) ++neg;
//If the sign changes, then point is outside
if (pos > 0 && neg > 0)
return 0;
}
return 1;
}
// the 4 vertices rendered do not make a convex quad
// we have to switch 2 vertices for that
// only works because we render 4 points left to right
void
makeConvex(uint16_t *points)
{
// little hack
uint16_t tmpX = points[6], tmpY = points[7];
points[6] = points[4];
points[7] = points[5];
points[4] = tmpX;
points[5] = tmpY;
}
void
fillQuads(uint8_t current_face)
{
makeConvex((uint16_t *)&vertices[current_face * 8]);
uint16_t top = UINT16_MAX, bot = 0, left = UINT16_MAX, right = 0;
for (uint8_t k = 0 ; k < 8 ; ++k) {
const uint16_t item = vertices[current_face * 8 + k];
if (k & 1) {
if (item > bot)
bot = item;
if (item < top)
top = item;
} else {
if (item > right)
right = item;
if (item < left)
left = item;
}
}
for (uint16_t y = top ; y <= bot; ++y) {
for (uint16_t x = left ; x <= right ; ++x) {
if (isInQuad(x, y, current_face))
putPx(x, y, current_face);
}
}
}
uint8_t
detect(uint8_t current_face)
{
for (uint8_t k = current_face * 8; k < current_face * 8 + 8; ++k)
if (vertices[k] == UINT16_MAX)
return 0;
return 1;
}
int
comp(const void *p1, const void *p2) {
FIXED_POINT left = *(const FIXED_POINT *)p1;
FIXED_POINT right = *(const FIXED_POINT *)p2;
return ((left > right) - (left < right));
}
void
detectAndFillQuads()
{
qsort((FIXED_POINT *)zBuffer, NUM_FACES, 2 * sizeof(FIXED_POINT), comp);
for (uint8_t idx = 0 ; idx < NUM_FACES ; ++idx) {
char ch = zBuffer[2 * idx + 1];
if (detect(ch))
fillQuads(ch);
}
}
void
printAscii()
{
detectAndFillQuads();
flipBuffers();
}
void
rotateCube(FIXED_POINT cubeX, FIXED_POINT cubeY, FIXED_POINT cubeZ, uint8_t ch)
{
struct Quaternions q = mult(&Current, cubeX, cubeY, cubeZ);
uint32_t x = q.x >> FP;
uint32_t y = q.y >> FP;
// not fixed point yet!!
float invZ = (1 << FP) / (float)(q.z + K2 * (1 << FP));
int32_t screenX = CUBE_WIDTH * 2 + (int32_t)((x) * K1) * invZ;
int32_t screenY = CUBE_WIDTH * 2 + (int32_t)((y) * K1) * invZ;
//TODO luminescence
if (screenX > GBA_SCREEN_W || screenX < 0
|| screenY > GBA_SCREEN_H || screenY < 0) return;
FIXED_POINT invZFixed = FLOAT2FIXED(invZ);
uint8_t firstEmptyVertex = ch * 8;
for ( ; vertices[firstEmptyVertex] != UINT16_MAX
&& firstEmptyVertex - ch * 8 < 8 ; firstEmptyVertex+=2);
vertices[firstEmptyVertex] = screenX;
vertices[firstEmptyVertex + 1] = screenY;
if (zBuffer[2 * ch] < invZFixed) {
zBuffer[2 * ch] = invZFixed;
zBuffer[2 * ch + 1] = ch;
}
}
void
interpolate(struct Quaternions *qa, struct Quaternions *qb)
{
frontFacingFace = -1;
float cosHalfTheta =
FIXED2FLOAT(MULT_FP(qa->w, qb->w) +
MULT_FP(qa->x, qb->x) +
MULT_FP(qa->y, qb->y) +
MULT_FP(qa->z, qb->z));
//if qa = qb or qa = -qb then theta = 0 and we can return qa
if (cosHalfTheta >= 1.0 || cosHalfTheta <= -1.0) {
goto exit;
}
if (cosHalfTheta < 0) {
qb->w = -qb->w;
qb->x = -qb->x;
qb->y = -qb->y;
qb->z = qb->z;
cosHalfTheta = -cosHalfTheta;
}
float halfTheta = acos(cosHalfTheta);
float sinHalfTheta = sqrt(1.0 - cosHalfTheta * cosHalfTheta);
//if theta = 180 degrees then result is not fully defined
// we could rotate around any axis normal to qa or qb
if (sinHalfTheta < 0.01 && sinHalfTheta > -0.01) {
qa->w = ((qa->w >> 1) + (qb->w >> 1));
qa->x = ((qa->x >> 1) + (qb->x >> 1));
qa->y = ((qa->y >> 1) + (qb->y >> 1));
qa->z = ((qa->z >> 1) + (qb->z >> 1));
goto exit;
}
FIXED_POINT ratioA = FLOAT2FIXED(sin((1 - FIXED2FLOAT(interpolationStep)) * halfTheta) / sinHalfTheta);
FIXED_POINT ratioB = FLOAT2FIXED(sin(FIXED2FLOAT(interpolationStep) * halfTheta) / sinHalfTheta);
qa->w = (MULT_FP(qa->w, ratioA) + MULT_FP(qb->w, ratioB));
qa->x = (MULT_FP(qa->x, ratioA) + MULT_FP(qb->x, ratioB));
qa->y = (MULT_FP(qa->y, ratioA) + MULT_FP(qb->y, ratioB));
qa->z = (MULT_FP(qa->z, ratioA) + MULT_FP(qb->z, ratioB));
exit:
interpolationStep += ACTION_STEP_FP;
}
void
handleAngle(uint8_t input)
{
// TODO
if (currentlyMoving == 0) {
currentlyMoving = input;
struct Quaternions tmp;
switch (input) {
case 'w':
case 'W':
tmp = GET_ROTATE_X_Q(M_PI_2);
break;
case 'a':
case 'A':
tmp = GET_ROTATE_Y_Q(-M_PI_2);
break;
case 's':
case 'S':
tmp = GET_ROTATE_X_Q(-M_PI_2);
break;
case 'd':
case 'D':
tmp = GET_ROTATE_Y_Q(M_PI_2);
break;
case 'q':
case 'Q':
tmp = GET_ROTATE_Z_Q(-M_PI_2);
break;
case 'e':
case 'E':
tmp = GET_ROTATE_Z_Q(M_PI_2);
break;
default:
currentlyMoving = 0;
return;
//TODO idle movement
}
multQ(&tmp, &Target);
Target = tmp;
normalize(&Target);
} else {
if (interpolationStep < (1 << FP) ) {
interpolate(&Current, &Target);
normalize(&Current);
}
else {
Current = Target;
interpolationStep = 0;
currentlyMoving = 0;
}
}
}
uint8_t
getInput()
{
// TODO
uint8_t c = 's';
handleAngle(c);
return c;
}
int
main()
{
REG_DISPCNT = DISPCNT_BG_MODE(4) | DISPCNT_BG2_ENABLE;
Current = GET_ROTATE_Z_Q(0);
init_colors();
while (1) {
memset(MEM_VRAM_MODE4, 0, GBA_SCREEN_H * GBA_SCREEN_W);
memset((uint16_t *)vertices, UINT16_MAX, sizeof(uint16_t) * NUM_FACES * 4 * 2);
//zBuff is not correct data struct, need a map or smth
memset((FIXED_POINT *)zBuffer, 0, NUM_FACES * 2 * sizeof(FIXED_POINT));
for (FIXED_POINT cubeX = -CUBE_WIDTH_FP + 1 * (1 << FP);
cubeX <= CUBE_WIDTH_FP - 1 * (1 << FP); cubeX += STEP_FP - 2 * (1 << FP)) {
for (FIXED_POINT cubeY = -CUBE_WIDTH_FP + 1 * (1 << FP);
cubeY <= CUBE_WIDTH_FP - 1 * (1 << FP); cubeY += STEP_FP - 2 * (1 << FP)) {
switch (frontFacingFace) {
case FACE_FRONT:
rotateCube(cubeX, cubeY, -CUBE_WIDTH_FP, FACE_FRONT);
break;
case FACE_LEFT:
rotateCube(-CUBE_WIDTH_FP, cubeX, cubeY, FACE_LEFT);
break;
case FACE_RIGHT:
rotateCube(CUBE_WIDTH_FP, cubeX, cubeY, FACE_RIGHT);
break;
case FACE_BOTTOM:
rotateCube(cubeX, -CUBE_WIDTH_FP, cubeY, FACE_BOTTOM);
break;
case FACE_TOP:
rotateCube(cubeX, CUBE_WIDTH_FP, cubeY, FACE_TOP);
break;
case FACE_BACK:
rotateCube(cubeX, cubeY, CUBE_WIDTH_FP, FACE_BACK);
break;
default: // idk render all
rotateCube(cubeX, cubeY, -CUBE_WIDTH_FP, FACE_FRONT);
rotateCube(-CUBE_WIDTH_FP, cubeX, cubeY, FACE_LEFT);
rotateCube(CUBE_WIDTH_FP, cubeX, cubeY, FACE_RIGHT);
rotateCube(cubeX, -CUBE_WIDTH_FP, cubeY, FACE_TOP);
rotateCube(cubeX, CUBE_WIDTH_FP, cubeY, FACE_BOTTOM);
rotateCube(cubeX, cubeY, CUBE_WIDTH_FP, FACE_BACK);
}
}
}
printAscii();
getInput();
}
}
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