-1
我编写了一个简单的自上而下的汽车驾驶游戏，类似于GameBoyAdvance上的第一个GTA。我只用矢量图形来做这件事，而GBA并没有很好地处理它;基本上有5个行人实例滞后。需要帮助优化C++
我没有太多优化代码的经验，所以我想知道是否可以对我的代码进行一些调整以使其运行速度更快，而不取决于它运行在GBA。
我使用的碰撞测试是SAT（分离轴定理），因为我发现它是用于矢量图形碰撞检查的最简单的测试;游戏本身非常简单。
下面是代码：
/*
GTA Vector City
Author: Alberto Taiuti
Version: 2.0
*/
#include "Global.h"
#include <string.h>
#include <cstdio>
#include "font.h"
#include "CVector2D.h"
#include "CCar.h"
#include "CPed.h"
#include <vector>
#include <memory>
/* GLOBAL VARIABLES */
void CheckCollisionsRect(CRect *test_a, CRect *test_b);
std::vector<CVector2D> PrepVectors(CRect *shape);
CVector2D GetMinMaxShape(std::vector<CVector2D> vect_shape, CVector2D axis);
void CheckCollisionRectVSPoint(CRect *test_a, CVector2D *point);
/* MAIN */
// The entry point for the game
int main()
{
// Frame counter
uint32_t frames = 0;
// Previous & current buttons states
static uint16_t prev_buttons = 0, cur_buttons = 0;
// Put the display into bitmap mode 3, and enable background 2.
REG_DISPCNT = MODE4 | BG2_ENABLE;
// Set up the palette.
SetPaletteBG(BLACK, RGB(0, 0, 0)); // black
SetPaletteBG(WHITE, RGB(31, 31, 31)); // white
SetPaletteBG(GREY, RGB(15, 15, 15)); // grey
SetPaletteBG(RED, RGB(31, 0, 0)); // red
SetPaletteBG(GREEN, RGB(0, 31, 0)); // green
SetPaletteBG(BLUE, RGB(0, 0, 31)); // blue
// Create car instance
CCar *car = new CCar(50,50);
// Create a building
/*CRect *test_b = new CRect(100.0f, 100.0f, 30, 30);
CRect *test_c = new CRect(120.0f, 120.0f, 30, 30);
CRect *test_d = new CRect(30.0f, 30.0f, 30, 30);*/
// Pedestrian instances
int ped_number = 10; // Number of pedestrians
std::vector<CPed*> peds; // Ped. entities container (made of smart pointers)
typedef std::vector<CPed*>::iterator p_itor; // Iterator
for(int i = 1; i <= ped_number; i++)
{
peds.push_back(new CPed(i, RED, 2.0f));
}
// Check whether the game is over
bool end = false;
// Main loop
while (!end)
{
// Flip the screen
FlipBuffers();
//Clear the screen
ClearScreen8(BLACK);
// Update frame counter
frames ++;
// Get the current state of the buttons.
cur_buttons = REG_KEYINPUT;
// Handle Input
car->HandleInput(prev_buttons, cur_buttons);
// Logic
car->Update();
for(int i = 0; i < ped_number; i++)
{
peds[i]->Update();
}
for(int i = 0; i < ped_number; i++)
{
CheckCollisionRectVSPoint(car->shape, peds[i]->pos);
}
/*CheckCollisionsRect(car->shape, test_b);
CheckCollisionsRect(car->shape, test_c);
CheckCollisionsRect(car->shape, test_d);
CheckCollisionRectVSPoint(car->shape, test_ped->pos);*/
// Render
car->Draw();
for(int i = 0; i < ped_number; i++)
{
peds[i]->Draw();
}
/*test_b->DrawFrame8(GREEN);
test_c->DrawFrame8(WHITE);
test_d->DrawFrame8(RED);
test_ped->Draw();*/
prev_buttons = cur_buttons;
// VSync
WaitVSync();
}
// Free memory
delete car;
//delete test_b; delete test_c; delete test_d;
//delete test_ped;
for(p_itor itor = peds.begin(); itor != peds.end(); itor ++)// Delete pedestrians
{
peds.erase(itor);
}
return 0;
}
void CheckCollisionsRect(CRect *test_a, CRect *test_b)
{
// If the two shapes are close enough, check for collision, otherways skip and save calculations to the CPU
//if((pow((test_a->points[0]->x - test_b->points[0]->x), 2) + pow((test_a->points[0]->y - test_b->points[0]->y), 2)) < 25.0f)
{
// Prepare the normals for both shapes
std::vector<CVector2D> normals_a = test_a->GetNormalsAsArray();
std::vector<CVector2D> normals_b = test_b->GetNormalsAsArray();
// Create two containers for holding the various vectors used for collision check
std::vector<CVector2D> vect_test_a = PrepVectors(test_a);
std::vector<CVector2D> vect_test_b = PrepVectors(test_b);
// Get the min and max vectors for each shape for each projection (needed for SAT)
CVector2D result_P1 = GetMinMaxShape(vect_test_a, normals_a[1]); //
CVector2D result_P2 = GetMinMaxShape(vect_test_b, normals_a[1]); //
// If the two objects are not colliding
if(result_P1.y < result_P2.x || result_P2.y < result_P1.x)
{
return;
}
CVector2D result_Q1 = GetMinMaxShape(vect_test_a, normals_a[0]); // First axis couple
CVector2D result_Q2 = GetMinMaxShape(vect_test_b, normals_a[0]); //
if(result_Q1.y < result_Q2.x || result_Q2.y < result_Q1.x)
{
return;
}
CVector2D result_R1 = GetMinMaxShape(vect_test_a, normals_b[1]); //
CVector2D result_R2 = GetMinMaxShape(vect_test_b, normals_b[1]); //
if(result_R1.y < result_R2.x || result_R2.y < result_R1.x)
{
return;
}
CVector2D result_S1 = GetMinMaxShape(vect_test_a, normals_b[0]); // Second axis couple
CVector2D result_S2 = GetMinMaxShape(vect_test_b, normals_b[0]); //
if(result_S1.y < result_S2.x || result_S2.y < result_S1.x)
{
return;
}
// Do something
PlotPixel8(200, 10, WHITE);
PlotPixel8(200, 11, WHITE);
PlotPixel8(200, 12, WHITE);
}
}
// Check for collision between an OOBB and a point
void CheckCollisionRectVSPoint(CRect *test_a, CVector2D *point)
{
// Prepare the normals for the shape
std::vector<CVector2D> normals_a = test_a->GetNormalsAsArray();
// Create a container for holding the various vectors used for collision check
std::vector<CVector2D> vect_test_a = PrepVectors(test_a);
// Get projections for the OOBB (needed for SAT)
CVector2D result_P1 = GetMinMaxShape(vect_test_a, normals_a[1]);
float result_point = point->DotProduct(normals_a[1]);
// If the two objects are not colliding on this axis
if(result_P1.y < result_point || result_point < result_P1.x)
{
return;
}
CVector2D result_Q1 = GetMinMaxShape(vect_test_a, normals_a[0]);
result_point = point->DotProduct(normals_a[0]);
// If the two objects are not colliding on this axis
if(result_Q1.y < result_point || result_point < result_Q1.x)
{
return;
}
// Do something
PlotPixel8(200, 10, WHITE);
PlotPixel8(200, 11, WHITE);
PlotPixel8(200, 12, WHITE);
}
// Returns a container with projection vectors for a given shape
std::vector<CVector2D> PrepVectors(CRect *shape)
{
std::vector<CVector2D> vect;
// Create vectors for projection and load them into the arrays
for(uint16_t i=0; i < 5; i++)
{
// Get global position of vectors and then add them to the array
vect.push_back(shape->GetVectorGlobal(i));
}
return vect;
}
CVector2D GetMinMaxShape(std::vector<CVector2D> vect_shape, CVector2D axis)
{
// Set initial minimum and maximum for shape's projection vectors
float min_proj = vect_shape[1].DotProduct(axis);
float max_proj = vect_shape[1].DotProduct(axis);
// Calculate max and min projection vectors by iterating along all of the corners
for(uint16_t i = 2; i < vect_shape.size(); i ++)
{
float current_proj = vect_shape[i].DotProduct(axis);
// Select minimum projection on axis
if(current_proj < min_proj) // If current projection is smaller than the minimum one
min_proj = current_proj;
// Select maximum projection on axis
if(current_proj > max_proj) // If current projection is greater than the minimum one
max_proj = current_proj;
}
return (CVector2D(min_proj, max_proj)); // Return a vector2D as it is a handy way for returning a couple of values
}
提前非常感谢大家在百忙之中乱码！
http://codereview.stackexchange.com上这可能会更好。然后再次，它可能不会，这取决于这些标题。 – chris
使用分析器查找程序的瓶颈。顺便说一句，似乎你做了很多的矢量副本......尝试通过* const引用*而不是*值*。 – Jarod42
@ Jarod42：在没有合适的分析器的情况下，因为我担心的是GBA的情况，您可以随时在不同区域戳背景颜色寄存器以可视化各个代码段使用的相对时间。 – doynax