Small3dLib demos

[WEREMSOFT]

Small3dLib demos works very well

Code:

#include <stdint.h>

unsigned char *frame_buffer;
uint16_t x_res, y_res;
uint8_t depth;

#define S3L_RESOLUTION_X x_res
#define S3L_RESOLUTION_Y y_res

int _main(void);

void main(void)
{
	_main();
}

#define S3L_PIXEL_FUNCTION drawPixel

#include "small3dlib.h"


void drawPixel(S3L_PixelInfo *p)
{
	char r, g, b;
	if (p->triangleIndex == 0 || p->triangleIndex == 1 ||
      p->triangleIndex == 4 || p->triangleIndex == 5)
	  {
		r = 0; g = 255, b = 0;
	  }
    
  else if (p->triangleIndex == 2 || p->triangleIndex == 3 ||
      p->triangleIndex == 6 || p->triangleIndex == 7)
	{
		r = 0; g = 0, b = 255;
	}
  else
    {
		r = 255; g = 0, b = 0;
	}


    putpixel(p->x, p->y, r, g, b);
}

S3L_Unit cubeVertices[] = { S3L_CUBE_VERTICES(S3L_F) };
S3L_Index cubeTriangles[] = { S3L_CUBE_TRIANGLES };

S3L_Model3D cubeModel; // 3D model, has a geometry, position, rotation etc.
S3L_Scene scene;       // scene we'll be rendring (can have multiple models)

int _main(void)
{
	// Gather video memory address, x & y resolution, and BPP
	frame_buffer = (unsigned char *)(*(uint64_t *)(0x5080));
	x_res = *(uint16_t *)(0x5088);
	y_res = *(uint16_t *)(0x508A);
	depth = 32;

	S3L_model3DInit(
		cubeVertices,
		S3L_CUBE_VERTEX_COUNT,
		cubeTriangles,
		S3L_CUBE_TRIANGLE_COUNT,
		&cubeModel); 

	S3L_sceneInit( // Initialize the scene we'll be rendering.
		&cubeModel,  // This is like an array with only one model in it.
		1,
		&scene);

	// shift the camera a little bit backwards so that it's not inside the cube:
	scene.camera.transform.translation.z = -2 * S3L_F;

	scene.models[0].transform.rotation.y += 45;
	scene.models[0].transform.rotation.x += 45;

	S3L_newFrame();        // has to be called before each frame
	S3L_drawScene(scene); 

}

void putpixel(int x, int y, char red, char green, char blue)
{
	int offset = ((y * x_res) + x) * (depth / 8);
	frame_buffer[offset+0] = blue;
	frame_buffer[offset+1] = green;
	frame_buffer[offset+2] = red;
}

[WEREMSOFT]

Video if the animated thing

Screencast.from.2024-07-21.14-31-31.webm

#include <stdint.h>

void putpixel(int x, int y, char red, char green, char blue);
void drawline(int x0, int y0, int x1, int y1, char red, char green, char blue);

unsigned char *frame_buffer;
uint16_t x_res, y_res;
uint8_t depth;

#define S3L_RESOLUTION_X x_res
#define S3L_RESOLUTION_Y y_res

int _main(void);
void usleep(uint64_t microseconds);

void main(void)
{
	_main();
}

#define S3L_PIXEL_FUNCTION drawPixel

#include "small3dlib.h"


void drawPixel(S3L_PixelInfo *p)
{
	char r, g, b;
	if (p->triangleIndex == 0 || p->triangleIndex == 1 ||
      p->triangleIndex == 4 || p->triangleIndex == 5)
	  {
		r = 0; g = 255, b = 0;
	  }
    
  else if (p->triangleIndex == 2 || p->triangleIndex == 3 ||
      p->triangleIndex == 6 || p->triangleIndex == 7)
	{
		r = 0; g = 0, b = 255;
	}
  else
    {
		r = 255; g = 0, b = 0;
	}


    putpixel(p->x, p->y, r, g, b);
}

S3L_Unit cubeVertices[] = { S3L_CUBE_VERTICES(S3L_F) };
S3L_Index cubeTriangles[] = { S3L_CUBE_TRIANGLES };

S3L_Model3D cubeModel; // 3D model, has a geometry, position, rotation etc.
S3L_Scene scene;       // scene we'll be rendring (can have multiple models)

int _main(void)
{
	// Gather video memory address, x & y resolution, and BPP
	frame_buffer = (unsigned char *)(*(uint64_t *)(0x5080));
	x_res = *(uint16_t *)(0x5088);
	y_res = *(uint16_t *)(0x508A);
	depth = 32;
	uint64_t frameBufferSize = x_res * y_res * 4;


	S3L_model3DInit(
		cubeVertices,
		S3L_CUBE_VERTEX_COUNT,
		cubeTriangles,
		S3L_CUBE_TRIANGLE_COUNT,
		&cubeModel); 

	S3L_sceneInit( // Initialize the scene we'll be rendering.
		&cubeModel,  // This is like an array with only one model in it.
		1,
		&scene);

	// shift the camera a little bit backwards so that it's not inside the cube:
	scene.camera.transform.translation.z = -2 * S3L_F;

	scene.models[0].transform.rotation.y += 45;
	scene.models[0].transform.rotation.x += 45;

	S3L_newFrame();        // has to be called before each frame
	S3L_drawScene(scene); 

  for (int i = 0; i < 200; ++i) // render 200 frames
  {
    // clear the screen
    for (int j = 0; j < frameBufferSize; ++j)
      frame_buffer[j] = 0;

    // for (int j = FRAME_OFFSET; j < SCREEN_SIZE; ++j)
    //   screen[j] = ((j - FRAME_OFFSET + 1) % (S3L_RESOLUTION_X + 1) ? ' ' : '\n');

    // screen[SCREEN_SIZE - 1] = 0; // terminate the string

    S3L_newFrame();        // has to be called before each frame
    S3L_drawScene(scene);  /* This starts the scene rendering. The drawPixel
                              function will be called to draw it. */

    usleep(100000);        // wait a bit to let the user see the frame

    // now move and rotate the cube a little to see some movement:
    scene.models[0].transform.rotation.y += 10;
    scene.models[0].transform.rotation.x += 4;
    scene.models[0].transform.translation.x = S3L_sin(i * 4);
    scene.models[0].transform.translation.y = S3L_sin(i * 2) / 2;
  }


}

void putpixel(int x, int y, char red, char green, char blue)
{
	int offset = ((y * x_res) + x) * (depth / 8);
	frame_buffer[offset+0] = blue;
	frame_buffer[offset+1] = green;
	frame_buffer[offset+2] = red;
}

// Función para leer el Time Stamp Counter
static inline uint64_t rdtsc(void) {
    uint32_t lo, hi;
    asm volatile ("rdtsc" : "=a" (lo), "=d" (hi));
    return ((uint64_t)hi << 32) | lo;
}

// Implementación de usleep utilizando rdtsc
void usleep(uint64_t microseconds) {
    // Supongamos una frecuencia de CPU de 3.0 GHz (ajusta según sea necesario)
    uint64_t cpu_frequency_hz = 3000000000;
    uint64_t cycles_to_wait = (cpu_frequency_hz / 1000000) * microseconds;

    uint64_t start = rdtsc();
    while ((rdtsc() - start) < cycles_to_wait) {
        // Espera ocupada (busy-wait)
    }
}

[IanSeyler]

This is amazing! Any specific build instructions for this?

[WEREMSOFT]

Yes. There is some things that needs to be modified in order to make it compile. Also I need to create a double buffer to avoid flickering and improve the delay to make it frame independent. Ill create some instructions hopefully this week.

[WEREMSOFT]

Ok, since I don't know when I'll be able to make a proper demo in a PR, I'll enumerate the basics:

Build

first, you need to download small3dlib.h, and put it in a place where your code can find when doing #include, in my case I put it in src/BareMetal-Demo/src/small3dlib.h.

Then you want to create a new .c file, I created mine named game.c, after that, you need to add this line in src/BareMetal-Demo/build.sh

	gcc -c -m64 -nostdlib -nostartfiles -nodefaultlibs -o game.o game.c
	ld -T c.ld -o ../bin/game.app game.o libBareMetal.o

In my case I put it under the line ld -T c.ld -o ../bin/gavare.app gavare.o

then you have to add the app to the demos, add this line to baremetal.sh

	./bmfs bmfs.img write game.app

Under the line ./bmfs bmfs.img write gavare.app will work just fine.

Run

You need to compile and install the new app, you can just type on your terminal

./baremetal.sh build && ./baremetal.sh demos && ./baremetal.sh run

the new application should appears in the dir

There are tons of cool demos in smal3dlib, should be fairly straightforward for anyone who wants to investigate.