shadow map test

main.c

#include <3ds.h>
#include <citro3d.h>
#include <string.h>
#include "vshader_shbin.h"
#include <stdio.h>

#define CLEAR_COLOR 0xFFB0D8D5

#define DISPLAY_TRANSFER_FLAGS \
	(GX_TRANSFER_FLIP_VERT(0) | GX_TRANSFER_OUT_TILED(0) | GX_TRANSFER_RAW_COPY(0) | \
	GX_TRANSFER_IN_FORMAT(GX_TRANSFER_FMT_RGBA8) | GX_TRANSFER_OUT_FORMAT(GX_TRANSFER_FMT_RGB8) | \
	GX_TRANSFER_SCALING(GX_TRANSFER_SCALE_NO))

typedef struct { float x, y, z; } vertex;

static const vertex vertex_list[] =
{
	{ 200.0f, 200.0f, 0.5f },
	{ 100.0f, 40.0f, 0.5f },
	{ 300.0f, 40.0f, 0.5f },
};

#define vertex_list_count (sizeof(vertex_list)/sizeof(vertex_list[0]))

static DVLB_s* vshader_dvlb;
static shaderProgram_s program;
static int uLoc_projection, uLoc_depth;
static C3D_Mtx projection;

static void* vbo_data;

int d = 2, s = 0;
int D = 10, S = 10;

int bb = 10, ss = 0;
int BB = 10, SS = 10;

static void sceneInit(void)
{
	// Load the vertex shader, create a shader program and bind it
	vshader_dvlb = DVLB_ParseFile((u32*)vshader_shbin, vshader_shbin_size);
	shaderProgramInit(&program);
	shaderProgramSetVsh(&program, &vshader_dvlb->DVLE[0]);
	C3D_BindProgram(&program);

	// Get the location of the uniforms
	uLoc_projection = shaderInstanceGetUniformLocation(program.vertexShader, "projection");
	uLoc_depth = shaderInstanceGetUniformLocation(program.vertexShader, "depth");

	// Configure attributes for use with the vertex shader
	C3D_AttrInfo* attrInfo = C3D_GetAttrInfo();
	AttrInfo_Init(attrInfo);
	AttrInfo_AddLoader(attrInfo, 0, GPU_FLOAT, 3); // v0=position
	AttrInfo_AddFixed(attrInfo, 1); // v1=color

	// Compute the projection matrix
	Mtx_OrthoTilt(&projection, 0.0, 400.0, 0.0, 240.0, 0.0, 1.0, true);

	// Create the VBO (vertex buffer object)
	vbo_data = linearAlloc(sizeof(vertex_list));
	memcpy(vbo_data, vertex_list, sizeof(vertex_list));

	// Configure buffers
	C3D_BufInfo* bufInfo = C3D_GetBufInfo();
	BufInfo_Init(bufInfo);
	BufInfo_Add(bufInfo, vbo_data, sizeof(vertex), 1, 0x0);

	// Configure the first fragment shading substage to just pass through the vertex color
	// See https://www.opengl.org/sdk/docs/man2/xhtml/glTexEnv.xml for more insight
	C3D_TexEnv* env = C3D_GetTexEnv(0);
	C3D_TexEnvSrc(env, C3D_Both, GPU_PRIMARY_COLOR, 0, 0);
	C3D_TexEnvOp(env, C3D_Both, 0, 0, 0);
	C3D_TexEnvFunc(env, C3D_Both, GPU_REPLACE);
}

C3D_Tex renderBuffer;
unsigned char* result;

static void sceneRender(void)
{
	// Update the uniforms
	C3D_FVUnifMtx4x4(GPU_VERTEX_SHADER, uLoc_projection, &projection);
	C3D_FVUnifSet(GPU_VERTEX_SHADER, uLoc_depth, (float)d/D, 0.0f, 0.0f, 0.0f);

	C3D_FragOpMode(GPU_FRAGOPMODE_SHADOW);

	// Set the fixed attribute (color)
	C3D_FixedAttribSet(1, 1.0, (float)s/S, 1.0, 1.0);

	C3D_DepthMap(false, -1.0f, 0.0f);
	C3D_DepthTest(false, 0, 0);

	C3D_FragOpShadow((float)ss / SS, (float)bb / BB);

	// Draw the VBO
	C3D_DrawArrays(GPU_TRIANGLES, 0, vertex_list_count);

	C3D_FrameSplit(0);

	GX_TextureCopy(renderBuffer.data, 0, (u32*)result, 0, 16 * 16 * 4, 8);
}

static void sceneExit(void)
{
	// Free the VBO
	linearFree(vbo_data);

	// Free the shader program
	shaderProgramFree(&program);
	DVLB_Free(vshader_dvlb);
}



void Decode(const unsigned char* data, float* d, float* s) {
	*d = (data[0] * 65536 + data[1] * 256 + data[2]) / 16777215.0f;
	*s = data[3] / 255.0f;
}


void updateText() {
    consoleClear();
	unsigned char* data = result;

	float d0, s0, d1, s1;
	GSPGPU_InvalidateDataCache(data, 16 * 16 * 4);
	Decode(data, &d0, &s0);
	Decode(data + 8 * 8 * 3 * 4, &d1, &s1);
	float scale = (float)ss / SS, bias = (float)bb / BB;
	printf("scale=%f, bias=%f\n", scale, bias);
	printf("before: d=%f, s=%f\n", d0, s0);
	float draw_d = (float)d/D, draw_s = (float)s/S;
	printf("draw:   d=%f, s=%f\n", draw_d, draw_s);
	printf("after:  d=%f, s=%f\n", d1, s1);
	float st = 1 / (bias + scale * (1 - draw_d / d0));
	st *= draw_s;
	if (st < 0) st = 0;
	if (st > s0) st = s0;
	printf("s theory = %f\n", st);
}

static PrintConsole bottomScreen;

int main()
{
	result = linearAlloc(16 * 16 * 4);
	// Initialize graphics
	gfxInitDefault();
	consoleInit(GFX_BOTTOM, &bottomScreen);
	consoleSelect(&bottomScreen);
	gfxSetDoubleBuffering(GFX_BOTTOM, true);

	C3D_Init(C3D_DEFAULT_CMDBUF_SIZE);

	C3D_TexInitVRAM(&renderBuffer, 16, 16, GPU_RGBA8);

	// Initialize the render target
	C3D_RenderTarget* target = C3D_RenderTargetCreateFromTex(&renderBuffer, GPU_TEXFACE_2D, 0, -1);
	C3D_RenderTargetSetClear(target, C3D_CLEAR_COLOR, CLEAR_COLOR, 0);

	// Initialize the scene
	sceneInit();

	// Main loop
	while (aptMainLoop())
	{
		hidScanInput();

		// Respond to user input
		u32 kDown = hidKeysDown();
		if (kDown & KEY_START)
			break; // break in order to return to hbmenu

		if (kDown & KEY_A) {
			d++;
			if (d == D+1)
				d = 0;
		}
		if (kDown & KEY_B) {
			s++;
			if (s == S+1)
				s = 0;
		}

		if (kDown & KEY_X) {
			ss++;
			if (ss == SS * 2 + 1)
				ss = -SS * 2;
		}

		if (kDown & KEY_Y) {
			bb++;
			if (bb == BB * 2 + 1)
				bb = -BB * 2;
		}


		// Render the scene
		C3D_FrameBegin(C3D_FRAME_SYNCDRAW);
			C3D_FrameDrawOn(target);
			sceneRender();
		C3D_FrameEnd(0);

		static int k = 0;

		if (k == 4)updateText();
		++k;
		k %= 8;
	}

	// Deinitialize the scene
	sceneExit();

	// Deinitialize graphics
	C3D_Fini();
	gfxExit();
	return 0;
}

vshader.v.pica

; Example PICA200 vertex shader

; Uniforms
.fvec projection[4]
.fvec depth

; Constants
.constf myconst(0.0, 1.0, -1.0, 0.1)
.constf myconst2(0.3, 0.0, 0.0, 0.0)
.alias  zeros myconst.xxxx ; Vector full of zeros
.alias  ones  myconst.yyyy ; Vector full of ones

; Outputs
.out outpos position
.out outclr color

; Inputs (defined as aliases for convenience)
.alias inpos v0
.alias inclr v1

.bool test

.proc main
	; Force the w component of inpos to be 1.0
	mov r0.xyz, inpos
	mov r0.w,   ones

	; outpos = projectionMatrix * inpos
	dp4 outpos.x, projection[0], r0
	dp4 outpos.y, projection[1], r0
	;dp4 outpos.z, projection[2], r0
	mov outpos.z, -depth.x
	dp4 outpos.w, projection[3], r0

	; outclr = inclr
	mov outclr, inclr

	; We're finished
	end
.end