libctru/examples/graphics/gpu/simple_tri/source/main.c

132 lines
3.7 KiB
C

/*
* ~~ Simple libctru GPU triangle example ~~
* This example demonstrates the basics of using the PICA200 in a 3DS homebrew
* application in order to render a basic scene consisting of a white solid triangle.
*/
#include "gpu.h"
#include "vshader_shbin.h"
#define CLEAR_COLOR 0x68B0D8FF
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;
static matrix_4x4 projection;
static void* vbo_data;
static void sceneInit(void)
{
// Load the vertex shader and create a shader program
vshader_dvlb = DVLB_ParseFile((u32*)vshader_shbin, vshader_shbin_size);
shaderProgramInit(&program);
shaderProgramSetVsh(&program, &vshader_dvlb->DVLE[0]);
// Get the location of the projection matrix uniform
uLoc_projection = shaderInstanceGetUniformLocation(program.vertexShader, "projection");
// Compute the projection matrix
m4x4_ortho_tilt(&projection, 0.0, 400.0, 0.0, 240.0, 0.0, 1.0);
// Create the VBO (vertex buffer object)
vbo_data = linearAlloc(sizeof(vertex_list));
memcpy(vbo_data, vertex_list, sizeof(vertex_list));
}
static void sceneRender(void)
{
// Bind the shader program
shaderProgramUse(&program);
// 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
GPU_SetTexEnv(0,
GPU_TEVSOURCES(GPU_PRIMARY_COLOR, GPU_PRIMARY_COLOR, GPU_PRIMARY_COLOR), // RGB channels
GPU_TEVSOURCES(GPU_PRIMARY_COLOR, GPU_PRIMARY_COLOR, GPU_PRIMARY_COLOR), // Alpha
GPU_TEVOPERANDS(0, 0, 0), // RGB
GPU_TEVOPERANDS(0, 0, 0), // Alpha
GPU_REPLACE, GPU_REPLACE, // RGB, Alpha
0xFFFFFFFF);
// Configure the "attribute buffers" (that is, the vertex input buffers)
GPU_SetAttributeBuffers(
1, // Number of inputs per vertex
(u32*)osConvertVirtToPhys((u32)vbo_data), // Location of the VBO
GPU_ATTRIBFMT(0, 3, GPU_FLOAT), // Format of the inputs (in this case the only input is a 3-element float vector)
0xFFE, // Unused attribute mask, in our case bit 0 is cleared since it is used
0x0, // Attribute permutations (here it is the identity)
1, // Number of buffers
(u32[]) { 0x0 }, // Buffer offsets (placeholders)
(u64[]) { 0x0 }, // Attribute permutations for each buffer (identity again)
(u8[]) { 1 }); // Number of attributes for each buffer
// Upload the projection matrix
GPU_SetFloatUniformMatrix(GPU_VERTEX_SHADER, uLoc_projection, &projection);
// Draw the VBO
GPU_DrawArray(GPU_TRIANGLES, 0, vertex_list_count);
}
static void sceneExit(void)
{
// Free the VBO
linearFree(vbo_data);
// Free the shader program
shaderProgramFree(&program);
DVLB_Free(vshader_dvlb);
}
int main()
{
// Initialize graphics
gfxInitDefault();
gpuInit();
// Initialize the scene
sceneInit();
gpuClearBuffers(CLEAR_COLOR);
// Main loop
while (aptMainLoop())
{
gspWaitForVBlank(); // Synchronize with the start of VBlank
gfxSwapBuffersGpu(); // Swap the framebuffers so that the frame that we rendered last frame is now visible
hidScanInput(); // Read the user input
// Respond to user input
u32 kDown = hidKeysDown();
if (kDown & KEY_START)
break; // break in order to return to hbmenu
// Render the scene
gpuFrameBegin();
sceneRender();
gpuFrameEnd();
gpuClearBuffers(CLEAR_COLOR);
// Flush the framebuffers out of the data cache (not necessary with pure GPU rendering)
//gfxFlushBuffers();
}
// Deinitialize the scene
sceneExit();
// Deinitialize graphics
gpuExit();
gfxExit();
return 0;
}