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Mouse Picking Example (#846)

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* Added mouse picking example.
This commit is contained in:
jcherlin
2016-07-09 23:41:38 -07:00
committed by Branimir Karadžić
parent d3221c3404
commit f04755f9a3
8 changed files with 496 additions and 0 deletions
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16
examples/30-picking/fs_picking_id.sc Normal file
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$input v_pos, v_view, v_normal, v_color0
/*
* Copyright 2011-2016 Branimir Karadzic. All rights reserved.
* License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
*/
#include "../common/common.sh"
uniform vec4 u_id;
void main()
{
gl_FragColor.xyz = u_id.xyz; // This is dumb, should use u8 texture
gl_FragColor.w = 1.0;
}

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examples/30-picking/fs_picking_shaded.sc Normal file
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$input v_pos, v_view, v_normal, v_color0
/*
* Copyright 2011-2016 Branimir Karadzic. All rights reserved.
* License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
*/
#include "../common/common.sh"
vec2 blinn(vec3 _lightDir, vec3 _normal, vec3 _viewDir)
{
float ndotl = dot(_normal, _lightDir);
vec3 reflected = _lightDir - 2.0*ndotl*_normal; // reflect(_lightDir, _normal);
float rdotv = dot(reflected, _viewDir);
return vec2(ndotl, rdotv);
}
float fresnel(float _ndotl, float _bias, float _pow)
{
float facing = (1.0 - _ndotl);
return max(_bias + (1.0 - _bias) * pow(facing, _pow), 0.0);
}
vec4 lit(float _ndotl, float _rdotv, float _m)
{
float diff = max(0.0, _ndotl);
float spec = step(0.0, _ndotl) * max(0.0, _rdotv * _m);
return vec4(1.0, diff, spec, 1.0);
}
void main()
{
vec3 lightDir = vec3(0.0, 0.0, -1.0);
vec3 normal = normalize(v_normal);
vec3 view = normalize(v_view);
vec2 bln = blinn(lightDir, normal, view);
vec4 lc = lit(bln.x, bln.y, 1.0);
float fres = fresnel(bln.x, 0.2, 5.0);
vec3 color = v_color0.xyz;
gl_FragColor.xyz = pow(vec3(0.07, 0.06, 0.08) + color*lc.y + fres*pow(lc.z, 128.0), vec3_splat(1.0/2.2) );
gl_FragColor.w = 1.0;
}

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examples/30-picking/makefile Normal file
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#
# Copyright 2011-2016 Branimir Karadzic. All rights reserved.
# License: http://www.opensource.org/licenses/BSD-2-Clause
#
BGFX_DIR=../..
RUNTIME_DIR=$(BGFX_DIR)/examples/runtime
BUILD_DIR=../../.build
include $(BGFX_DIR)/scripts/shader.mk
rebuild:
@make -s --no-print-directory TARGET=0 clean all
@make -s --no-print-directory TARGET=1 clean all
@make -s --no-print-directory TARGET=2 clean all
@make -s --no-print-directory TARGET=3 clean all
@make -s --no-print-directory TARGET=4 clean all
@make -s --no-print-directory TARGET=5 clean all

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examples/30-picking/picking.cpp Normal file
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/*
* Copyright 2011-2016 Branimir Karadzic. All rights reserved.
* License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
*/
#include "common.h"
#include "bgfx_utils.h"
#include "imgui/imgui.h"
#include <bx/rng.h>
#include <map>
#define RENDER_PASS_SHADING 0 // Default forward rendered geo with simple shading
#define RENDER_PASS_ID 1 // ID buffer for picking
#define RENDER_PASS_BLIT 2 // Blit GPU render target to CPU texture
#define ID_DIM 8 // Size of the ID buffer
class ExamplePicking : public entry::AppI
{
void init(int _argc, char** _argv) BX_OVERRIDE
{
Args args(_argc, _argv);
m_width = 1280;
m_height = 720;
m_debug = BGFX_DEBUG_TEXT;
m_reset = BGFX_RESET_VSYNC;
bgfx::init(args.m_type, args.m_pciId);
bgfx::reset(m_width, m_height, m_reset);
// Enable debug text.
bgfx::setDebug(m_debug);
// Set up screen clears
bgfx::setViewClear(RENDER_PASS_SHADING
, BGFX_CLEAR_COLOR|BGFX_CLEAR_DEPTH
, 0x303030ff
, 1.0f
, 0
);
// ID buffer clears to black, which represnts clicking on nothing (background)
bgfx::setViewClear(RENDER_PASS_ID
, BGFX_CLEAR_COLOR | BGFX_CLEAR_DEPTH
, 0x000000ff
, 1.0f
, 0
);
// Create uniforms
u_tint = bgfx::createUniform("u_tint", bgfx::UniformType::Vec4); // Tint for when you click on items
u_id = bgfx::createUniform("u_id", bgfx::UniformType::Vec4); // ID for drawing into ID buffer
// Create program from shaders.
m_shadingProgram = loadProgram("vs_picking_shaded", "fs_picking_shaded"); // Blinn shading
m_idProgram = loadProgram("vs_picking_shaded", "fs_picking_id"); // Shader for drawing into ID buffer
const char * meshPaths[] = {"meshes/orb.bin", "meshes/column.bin", "meshes/bunny.bin", "meshes/cube.bin", "meshes/tree.bin", "meshes/hollowcube.bin"};
const float meshScale[] = {0.5f, 0.05f, 0.5f, 0.25f, 0.05f, 0.05f};
bx::RngMwc mwc; // Random number generator
for (int32_t i = 0; i < 12; i++) {
m_meshes[i] = meshLoad(meshPaths[i%6]);
m_meshScale[i] = meshScale[i%6];
// For the sake of this example, we'll give each mesh a random color, so the debug output looks colorful.
// In an actual app, you'd probably just want to count starting from 1
uint32_t r = mwc.gen() % 256;
uint32_t g = mwc.gen() % 256;
uint32_t b = mwc.gen() % 256;
m_idsF[i][0] = r/255.0f;
m_idsF[i][1] = g/255.0f;
m_idsF[i][2] = b/255.0f;
m_idsF[i][3] = 1.0f;
m_idsU[i] = (r)+(g << 8) + (b << 16) + (255u << 24);
}
m_timeOffset = bx::getHPCounter();
// Set up ID buffer, which has a color target and depth buffer
m_pickingRT = bgfx::createTexture2D(ID_DIM, ID_DIM, 1, bgfx::TextureFormat::RGBA8, // Probably would be better to use unsigned format
// but currently doesn't display in imgui
0
| BGFX_TEXTURE_RT
| BGFX_TEXTURE_MIN_POINT
| BGFX_TEXTURE_MAG_POINT
| BGFX_TEXTURE_MIP_POINT
| BGFX_TEXTURE_U_CLAMP
| BGFX_TEXTURE_V_CLAMP
);
m_pickingRTDepth = bgfx::createTexture2D(ID_DIM, ID_DIM, 1, bgfx::TextureFormat::D24S8,
0
| BGFX_TEXTURE_RT
| BGFX_TEXTURE_MIN_POINT
| BGFX_TEXTURE_MAG_POINT
| BGFX_TEXTURE_MIP_POINT
| BGFX_TEXTURE_U_CLAMP
| BGFX_TEXTURE_V_CLAMP
);
// CPU texture for blitting to and reading ID buffer so we can see what was clicked on
// Impossible to read directly from a render target, you *must* blit to a CPU texture first.
// Algorithm Overview:
// Render on GPU -> Blit to CPU texture -> Read from CPU texture
m_blitTex = bgfx::createTexture2D(ID_DIM, ID_DIM, 1, bgfx::TextureFormat::RGBA8,
0
| BGFX_TEXTURE_BLIT_DST // <==
| BGFX_TEXTURE_READ_BACK // <==
| BGFX_TEXTURE_MIN_POINT
| BGFX_TEXTURE_MAG_POINT
| BGFX_TEXTURE_MIP_POINT
| BGFX_TEXTURE_U_CLAMP
| BGFX_TEXTURE_V_CLAMP
);
bgfx::TextureHandle rt[2] = { m_pickingRT, m_pickingRTDepth };
m_pickingFB = bgfx::createFrameBuffer(BX_COUNTOF(rt), rt, true);
imguiCreate();
}
int shutdown() BX_OVERRIDE
{
for (int32_t i = 0; i < 12; i++) {
meshUnload(m_meshes[i]);
}
// Cleanup.
bgfx::destroyProgram(m_shadingProgram);
bgfx::destroyProgram(m_idProgram);
bgfx::destroyUniform(u_tint);
bgfx::destroyUniform(u_id);
bgfx::destroyFrameBuffer(m_pickingFB);
bgfx::destroyTexture(m_pickingRT);
bgfx::destroyTexture(m_pickingRTDepth);
bgfx::destroyTexture(m_blitTex);
imguiDestroy();
// Shutdown bgfx.
bgfx::shutdown();
return 0;
}
bool update() BX_OVERRIDE
{
if (!entry::processEvents(m_width, m_height, m_debug, m_reset, &m_mouseState) )
{
bgfx::setViewFrameBuffer(RENDER_PASS_ID, m_pickingFB);
int64_t now = bx::getHPCounter();
static int64_t last = now;
const int64_t frameTime = now - last;
last = now;
const double freq = double(bx::getHPFrequency());
const double toMs = 1000.0 / freq;
float time = (float)((bx::getHPCounter() - m_timeOffset) / double(bx::getHPFrequency()));
// Use debug font to print information about this example.
bgfx::dbgTextClear();
bgfx::dbgTextPrintf(0, 1, 0x4f, "bgfx/examples/30-picking");
bgfx::dbgTextPrintf(0, 2, 0x6f, "Description: Mouse picking.");
bgfx::dbgTextPrintf(0, 3, 0x0f, "Frame: % 7.3f[ms]", double(frameTime)*toMs);
// Set up matrices for basic forward renderer
const float camSpeed = 0.25;
float cameraSpin = (float)m_cameraSpin;
float eyeDist = 2.5f;
float eye[3] = { -eyeDist * bx::fsin(time*cameraSpin*camSpeed), 0.0f, -eyeDist * bx::fcos(time*cameraSpin*camSpeed) };
float at[3] = { 0.0f, 0.0f, 0.0f };
float view[16];
bx::mtxLookAt(view, eye, at);
float proj[16];
bx::mtxProj(proj, 60.0f, float(m_width)/float(m_height), 0.1f, 100.0f);
// Set up view rect and transform for the shaded pass
bgfx::setViewRect(RENDER_PASS_SHADING, 0, 0, uint16_t(m_width), uint16_t(m_height));
bgfx::setViewTransform(RENDER_PASS_SHADING, view, proj);
// Set up picking pass
float pickView[16];
float pickAt[4]; // Need to inversly project the mouse pointer to determin what we're looking at
float pickEye[3] = { eye[0], eye[1], eye[2] }; // Eye is same location as before
float viewProj[16];
bx::mtxMul(viewProj, view, proj);
float invViewProj[16];
bx::mtxInverse(invViewProj, viewProj);
// Mouse coord in NDC
float mouseXNDC = (m_mouseState.m_mx / (float)m_width) * 2.0f - 1.0f;
float mouseYNDC = ((m_height-m_mouseState.m_my) / (float)m_height) * 2.0f - 1.0f;
float mousePosNDC[4] = { mouseXNDC, mouseYNDC, 0, 1.0f };
// Unproject and perspective divide
bx::vec4MulMtx(pickAt, mousePosNDC, invViewProj);
pickAt[3] = 1.0f/pickAt[3];
pickAt[0] *= pickAt[3];
pickAt[1] *= pickAt[3];
pickAt[2] *= pickAt[3];
// Look at our unprojected point
bx::mtxLookAt(pickView, pickEye, pickAt);
float pickProj[16];
// Tight FOV is best for picking
bx::mtxProj(pickProj, m_fov, 1, 0.1f, 100.0f);
// View rect and transforms for picking pass
bgfx::setViewRect(RENDER_PASS_ID, 0, 0, ID_DIM, ID_DIM);
bgfx::setViewTransform(RENDER_PASS_ID, pickView, pickProj);
// Now that our passes are set up, we can finally draw each mesh
// Picking highlights a mesh so we'll set up this tint color
const float tintBasic[4] = { 1.0f, 1.0f, 1.0f, 1.0f };
const float tintHighlighted[4] = { 0.3f, 0.3f, 2.0f, 1.0f };
for (uint32_t m = 0; m < 12; m++) {
// Set up transform matrix for each mesh
float mtxRot[16];
bx::mtxRotateXY(mtxRot
, 0.0f
, time*0.37f*(m % 2 ? 1.0f : -1.0f)
);
float mtxScale[16];
float scale = m_meshScale[m];
bx::mtxScale(mtxScale
, scale
, scale
, scale
);
float mtxTrans[16];
bx::mtxTranslate(mtxTrans
, (m%4)-1.5f
, (m/4)-1.25f
, 0.0f
);
float mtx[16];
float mtxTransScale[16];
bx::mtxMul(mtxTransScale, mtxScale, mtxTrans);
bx::mtxMul(mtx, mtxRot, mtxTransScale);
// Submit mesh to both of our render passes
// Set uniform based on if this is the highlighted mesh
bgfx::setUniform(u_tint, m == m_highlighted ? tintHighlighted : tintBasic);
meshSubmit(m_meshes[m], RENDER_PASS_SHADING, m_shadingProgram, mtx);
// Submit ID pass based on mesh ID
bgfx::setUniform(u_id, m_idsF[m]);
meshSubmit(m_meshes[m], RENDER_PASS_ID, m_idProgram, mtx);
}
// If the user previously clicked, and we're done reading data from GPU, look at ID buffer on CPU
// Whatever mesh has the most pixels in the ID buffer is the one the user clicked on.
if (m_reading == m_currFrame) {
m_reading = 0;
std::map<uint32_t, uint32_t> ids; // This contains all the IDs found in the buffer
uint32_t maxAmount = 0;
for (uint8_t *x = m_blitData; x < m_blitData + ID_DIM * ID_DIM * 4;) {
uint8_t r = *x++;
uint8_t g = *x++;
uint8_t b = *x++;
uint8_t a = *x++;
const bgfx::Caps* caps = bgfx::getCaps();
if (bgfx::RendererType::Direct3D9 == caps->rendererType) {
// Comes back as BGRA
uint8_t temp = r;
r = b;
b = temp;
}
if (r == 0 && g == 0 && b == 0) // Skip background
continue;
uint32_t hashKey = (r)+(g<<8)+(b<<16)+(a<<24);
std::map<uint32_t, uint32_t>::iterator mapIter = ids.find(hashKey);
uint32_t amount = 1;
if (mapIter != ids.end()) {
amount = mapIter->second + 1;
}
ids[hashKey] = amount; // Amount of times this ID (color) has been clicked on in buffer
maxAmount = maxAmount > amount ? maxAmount : amount;
}
uint32_t idKey = 0;
m_highlighted = UINT32_MAX;
if (maxAmount) {
for (std::map<uint32_t, uint32_t>::iterator mapIter = ids.begin(); mapIter != ids.end(); mapIter++) {
if (mapIter->second == maxAmount) {
idKey = mapIter->first;
break;
}
}
for (uint32_t i = 0; i < 12; i++) {
if (m_idsU[i] == idKey) {
m_highlighted = i;
break;
}
}
}
}
// Start a new readback?
if (!m_reading && m_mouseState.m_buttons[entry::MouseButton::Left]) {
// Blit and read
bgfx::blit(RENDER_PASS_BLIT, m_blitTex, 0, 0, m_pickingRT);
m_reading = bgfx::readTexture(m_blitTex, m_blitData);
}
// Draw UI
imguiBeginFrame(m_mouseState.m_mx
, m_mouseState.m_my
, (m_mouseState.m_buttons[entry::MouseButton::Left] ? IMGUI_MBUT_LEFT : 0)
| (m_mouseState.m_buttons[entry::MouseButton::Right] ? IMGUI_MBUT_RIGHT : 0)
| (m_mouseState.m_buttons[entry::MouseButton::Middle] ? IMGUI_MBUT_MIDDLE : 0)
, m_mouseState.m_mz
, m_width
, m_height
);
imguiBeginArea("Picking Render Target:", 10, 100, 300, 400);
imguiImage(m_pickingRT, 1.0f, 1.0f, 1.0f);
imguiSlider("FOV", m_fov, 1.0f, 60.0f, 1.0f);
if (imguiCheck("Spin Camera", m_cameraSpin)) {
m_cameraSpin = !m_cameraSpin;
}
imguiEndArea();
imguiEndFrame();
// Advance to next frame. Rendering thread will be kicked to
// process submitted rendering primitives.
m_currFrame = bgfx::frame();
return true;
}
return false;
}
uint32_t m_width;
uint32_t m_height;
uint32_t m_debug;
uint32_t m_reset;
int64_t m_timeOffset;
entry::MouseState m_mouseState;
Mesh* m_meshes[12];
float m_meshScale[12];
float m_idsF[12][4];
uint32_t m_idsU[12];
uint32_t m_highlighted = UINT32_MAX;
// Resource handles
bgfx::ProgramHandle m_shadingProgram;
bgfx::ProgramHandle m_idProgram;
bgfx::UniformHandle u_tint;
bgfx::UniformHandle u_id;
bgfx::TextureHandle m_pickingRT;
bgfx::TextureHandle m_pickingRTDepth;
bgfx::TextureHandle m_blitTex;
bgfx::FrameBufferHandle m_pickingFB;
uint8_t m_blitData[ID_DIM*ID_DIM*4]; // Read blit into this
uint32_t m_reading = 0;
uint32_t m_currFrame = UINT32_MAX;
// UI
float m_fov = 3.0f;
bool m_cameraSpin = false;
};
ENTRY_IMPLEMENT_MAIN(ExamplePicking);

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examples/30-picking/varying.def.sc Normal file
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vec4 v_color0 : COLOR0 = vec4(1.0, 0.0, 0.0, 1.0);
vec3 v_normal : NORMAL = vec3(0.0, 0.0, 1.0);
vec2 v_texcoord0 : TEXCOORD0 = vec2(0.0, 0.0);
vec3 v_pos : TEXCOORD1 = vec3(0.0, 0.0, 0.0);
vec3 v_view : TEXCOORD2 = vec3(0.0, 0.0, 0.0);
vec3 a_position : POSITION;
vec4 a_color0 : COLOR0;
vec2 a_texcoord0 : TEXCOORD0;
vec3 a_normal : NORMAL;

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examples/30-picking/vs_picking_shaded.sc Normal file
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$input a_position, a_normal
$output v_pos, v_view, v_normal, v_color0
/*
* Copyright 2011-2016 Branimir Karadzic. All rights reserved.
* License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
*/
#include "../common/common.sh"
uniform vec4 u_tint;
void main()
{
vec3 pos = a_position;
vec3 normal = a_normal.xyz*2.0 - 1.0;
gl_Position = mul(u_modelViewProj, vec4(pos, 1.0) );
v_pos = gl_Position.xyz;
v_view = mul(u_modelView, vec4(pos, 1.0) ).xyz;
v_normal = mul(u_modelView, vec4(normal, 0.0) ).xyz;
v_color0 = u_tint*vec4(0.8, 0.8, 0.8, 1.0);
}

1
scripts/genie.lua
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@@ -391,6 +391,7 @@ exampleProject("26-occlusion")
exampleProject("27-terrain")
exampleProject("28-wireframe")
exampleProject("29-debugdraw")
exampleProject("30-picking")
-- C99 source doesn't compile under WinRT settings
if not premake.vstudio.iswinrt() then