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通過750 - 鼠標坐標,把原點在左上角的鼠標坐標變成左下角
實現輸入數據后的坐標系同GPU原點在左下角坐標相同,
比數組0,0對應左上角好,
此時實際上數組0,0對應左下角
#include <raylib.h>
// 感受:雖然是根據已有的經驗進行移植,
//但是追隨當時無中生有的過程,去理解當時如何基于最直接的窮舉想出來的,
//沿著同樣的測試窮舉而不是照抄,因為有了另一個坐標系GPU左下角和鼠標左上角原點不同
//根據5.測試正方向 的注釋:數格子發現一行一行對應之后,再修改鼠標坐標系,產生新的坐標學習
int main() {int **map;map = new int*[750 / 30];for (int i = 0; i < 25; i++) {map[i] = new int[25];}for (int i = 0; i < 25; i++) {for (int j = 0; j < 25; j++) {map[i][j] = 0;}}// 初始化窗口InitWindow(750, 750, "test for location");
// 設置GPU可以操作的畫布,一定要再初始化窗口之后才行,實際上是OpenGL的上下文,或者說默認環境設置RenderTexture2D mesh = LoadRenderTexture(750, 750);
// 設置幀率SetTargetFPS(160);
// 設置默認繪制到meshBeginTextureMode(mesh);for (int i = 0; i < 25; i++) {for (int j = 0; j < 25; j++) {
// 繪制矩形,原點(0,0)在左下角,現在是從左下角一行一行往上繪制if (map[i][j] == 0) {DrawRectangle(j * 30, i * 30, 30, 30, {255, 255, 255, 255});}if (i == 0 || j == 0 || i == 24 || j == 24) {DrawRectangle(j * 30, i * 30, 30, 30, {0, 255, 255, 255});}}}
// 取消繪制的GPU畫布EndTextureMode();
// 設置默認繪制到桌面BeginDrawing();
// 黑色覆蓋全部屏幕ClearBackground(BLACK);DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {0, 0, 750, 750}, {0, 0}, 0, WHITE);
// 結束繪制的桌面EndDrawing();
// 這里開始主循環int drawx;int drawy;int mousex;int mousey;int drawi;int drawj;mousex = 0;mousey = 0;drawx = 0;drawy = 0;drawi = 0;drawj = 0;while (!WindowShouldClose()) {
// 如果鼠標左鍵按下if (IsMouseButtonDown(MOUSE_BUTTON_LEFT)) {
// drawx = GetMousePosition().x;
// 無中生有坐標系變化過程
// 750,實際窮舉描述得到,在點一下,在鼠標坐標系是0,100,靠頂邊,
// 在GPU坐標系里0,100則是靠底邊100像素,
// 然后實際上是直接取反然后加上高度上限,發現原來可以
// 最后重整舊測試代碼實現
// drawy = 750 - GetMousePosition().y;
// drawy = 751 - GetMousePosition().y;
// if (drawx < 0 || drawx > 750 || drawy < 0 || drawy > 750)
// 發現可以直接寫,標注數據變化,于是重新命名變量mousex = GetMousePosition().x;mousey = GetMousePosition().y;
// 測試之后,追加等號,發現等號設置在0處解決問題,750-0=750,750/30=25,數組出界,750-1=749,749/30=24,
// 可知減的多,不出界,剩下的少,于是就不出界if (mousex < 0 || mousex > 750 || mousey <= 0 || mousey > 750) {
// 如果出界就不繪制,因為長按時鼠標超出窗口仍然可以檢測} else {
// 進行坐標系變換,禁用了原理代碼drawx = mousex;drawy = 750 - mousey;drawj = drawx / 30;drawi = drawy / 30;map[drawi][drawj] = 1;}}// 設置默認繪制到meshBeginTextureMode(mesh);for (int i = 0; i < 25; i++) {for (int j = 0; j < 25; j++) {
// 繪制矩形,原點(0,0)在左下角,現在是從左下角一行一行往上繪制if (map[i][j] == 0) {DrawRectangle(j * 30, i * 30, 30, 30, {255, 255, 255, 255});} else if (map[i][j] == 1) {DrawRectangle(j * 30, i * 30, 30, 30, {255, 0, 0, 255});}
// 測試邊界繪制時,禁用,看閃退有無時測試
// if (i == 0 || j == 0 || i == 24 || j == 24) {
// DrawRectangle(j * 30, i * 30, 30, 30, {0, 255, 255, 255});
// }if (i == 0 || j == 0 || i == 24 || j == 24) {DrawRectangle(j * 30, i * 30, 30, 30, {0, 255, 255, 255});}}}
// 取消繪制的GPU畫布EndTextureMode();// 設置默認繪制到桌面BeginDrawing();
// 黑色覆蓋全部屏幕ClearBackground(BLACK);
// DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {0, 0, 750, 750}, {0, 0}, 0, WHITE);
// 右移動100像素
// DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {100, 0, 750, 750}, {0, 0}, 0, WHITE);
// 左移動100像素
// DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {0, 0, 750, 750}, {100, 0}, 0, WHITE);
// 縮小到75*75大小像素
// DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {0, 0, 75, 75}, {0, 0}, 0, WHITE);
// 平移縮小的矩形右100像素
// DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {100, 0, 75, 75}, {0, 0}, 0, WHITE);
// 抵消
// DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {100, 0, 75, 75}, {100, 0}, 0, WHITE);
// 下移100像素
// DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {0, 100, 75, 75}, {0, 0}, 0, WHITE);
// 抵消了下移,回到原地,可知是上移
// DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {0, 100, 75, 75}, {0, 100}, 0, WHITE);
// 實錘上移像素
// DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {0, 0, 75, 75}, {0, 50}, 0, WHITE);
// 得出結論:后面的括號是管往左移動,往上移動,前面括號的兩個數字往右,往下移動調節
// DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {0, 0, 75, 75}, {0, 50}, 0, WHITE);
// 但是可以負數反向,實現在一個括號里實現移動效果,可知是對應不同坐標系下,提供的快速適應方案
// DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {0, 0, 75, 75}, {0, -50}, 0, WHITE);
// 恢復原樣DrawTexturePro(mesh.texture, {0, 0, 750, 750}, {0, 0, 750, 750}, {0, 0}, 0, WHITE);DrawText(TextFormat("mouseV1 %.0f,%.0f", GetMousePosition().x, GetMousePosition().y), 35, 12, 30, BLUE);DrawText(TextFormat("mouseV2 %.0f,%.0f", GetMousePosition().x, 750 - GetMousePosition().y), 35, 62, 30, BLUE);DrawText(TextFormat("drawjiV2 %d,%d", drawj, drawi), 35, 92, 30, BLUE);DrawText(TextFormat("drawxyV2 %d,%d", drawx, drawy), 35, 122, 30, BLUE);
// 結束繪制的桌面EndDrawing();}
}