OpenGL超大分辨率图像显示
OpenGL + GLSL shader + GLM + OpenCV
分块渲染（Tiled Rendering）
1）将大图像拆分为多个小块（Tile），渲染整幅图像分解为每次绘制一块（Tile）图像，绘制多次，确保每块图像的纹理尺寸不超过OpenGL设备支持的纹理尺寸；
2）每绘制一块图像，对应绘制两个三角形（(0,0)，（1，1）单位矩形内的两个三角形），通过修改ModelMatrix，每次将两个三角形绘制在窗口的不同区域范围内，对ModelMatrix的修改包括平移和缩放两个部分（见代码RenderPattern接口实现）；
由此，经过ModelMatrix矩阵变换后，所有Tile拼接之后的图像的坐标都在0,1区间内。
另外具体需要关注的几个问题有：
1）Tile如何定义，如何划分Tile；Tile的划分可预先查询当前OpenGL设备支持的最大纹理尺寸，不同的像素格式，支持的最大纹理尺寸是不同的，比如32位单通道图像最大尺寸的查询方法如下：
GLint internalFormat = GL_R32F;GLint max_size;glGetInternalformativ(GL_TEXTURE_2D, internalFormat, GL_MAX_WIDTH, 1, &max_size);glGetInternalformativ(GL_TEXTURE_2D, internalFormat, GL_MAX_HEIGHT, 1, &max_size);2）如何实现以鼠标所在位置为中心进行放缩，如何鼠标交互平移；（参见ZoomIn、ZoomOut接口）；
3）此代码实现的图像绘制，图像并没有填充整个Viewport，这个跟ProjectionMatrix的定义也有关系，具体可参见代码。
部分关键代码如下：
bigimage.vert (GLSL着色器文件)
#version 450 core
layout(location = 0) in vec2 position;
layout(location = 1) in vec2 texCoord;uniform mat4 projection;
uniform mat4 view;
uniform mat4 model;out vec2 fragTexCoord;void main() {gl_Position = projection * view * model * vec4(position, 0.0, 1.0);gl_Position.y = - gl_Position.y; // Flip Y coordinate for OpenGLfragTexCoord = texCoord;
}bigimage.frag (GLSL着色器文件）
#version 450 corein vec2 fragTexCoord;
out vec4 color;uniform sampler2D imageTexture;
uniform int imgType;uniform vec2 normalizeRange = vec2(0.0, 1.0);void main()
{if (imgType == 0 || imgType == 5) // CV_8UC1 / CV_32FC1{float gray = texture(imageTexture, fragTexCoord).r;if(imgType == 5) // CV_32FC1{gray = (gray - normalizeRange.x) / (normalizeRange.y - normalizeRange.x);}color = vec4(gray, gray, gray, 1.0);}else if(imgType == 16 || imgType == 21) // CV_8UC3 / CV_32FC3{vec3 val = texture(imageTexture, fragTexCoord).rgb;color = vec4(val.b, val.g, val.r, 1.0);}
}BigImageRenderer.h
#pragma once#include<opencv2/opencv.hpp>#include<map>
#include<GL/glew.h>
#include<glm/glm.hpp>
#include<vector>
#include"Shader.h"
#include<condition_variable>
#include<mutex>#define UNDEFINED_TEXTURE 999// 图像块结构
struct ImageTile {GLuint textureID = UNDEFINED_TEXTURE;int x, y; // 块坐标int width, height; // 块尺寸bool loaded;
};struct ProjectRange
{float minX, maxX;float minY, maxY;float xspan;float yspan;
};// A renderer class for renderering text displayed by a font loaded using the
// Freetype library. A single font is loaded, processed into a list of Character
// items for later rendering.
class BigImageRenderer
{
public:// Shader used for text rendering Shader shader;void setFileInfo(std::string path);std::string filepath;std::string locFolder;std::string filename;std::vector<cv::Mat> rgb;glm::mat4 projection;glm::mat4 view;glm::vec2 viewPosition;float zoomLevel=1.0f;const int tileSize = 4096;
//const int tileSize = 4096;
std::vector<ImageTile> tiles;
std::thread loaderThread;
std::mutex tileMutex;
std::atomic<bool> running;
float imageRatio = 1.0f;ProjectRange scope;// Constructor
BigImageRenderer();
void init(glm::ivec2 pos, glm::ivec2 size, GLint textureId, int screenW = 0, int screenH = 0);
~BigImageRenderer();void setRenderUsePseudoColor(bool flag);void updateProjectionMatrix();// 输入图像点像素坐标，
// 返回渲染窗口坐标 [-1,1]
glm::vec2 convert2RenderCS(glm::vec2 uv);
std::vector<glm::vec2> convert2RenderCS(std::vector<glm::vec2> uv);
void copyROI(BigImageRenderer* render);// 返回图像的像素坐标
glm::vec2 queryImageCoord(const float &xpos, const float &ypos);void loadData(const cv::Mat &data);
void updateImg(const cv::Mat &img, const bool &flipY = false);void setMousePos(const float &posx, const float &posy);
void RenderPattern(bool updateViewport = true);void setNormalizeRange(const float &low, const float &high);void zoomIn();void zoomOut();void updateOffset(const float &offsetX, const float &offsetY);glm::vec3 queryValue(const float &x, const float &y);glm::vec3 queryPixelValue(glm::vec2 pixel);GLuint texture;bool isInWindow(const glm::vec2 &pos, bool updateActiveStatus = false);bool isTranslating = false;bool render8bitImage = true;void updateViewPort(){glViewport(pos.x, pos.y, width, height);}void updateRenderParas();void createTiles();void loadVisibleTiles();void loadTile(ImageTile& tile);bool active = false;void reset(); // 清空cv::Mat imgGray; // 灰度图像bool usePseudoColor = false;bool isSelectingRoi = false;void initSelectRoi(double xpos, double ypos);void updateRoi(double xpos, double ypos);cv::Rect roi;cv::Mat roiMask;int rowMin, rowMax;int colMin, colMax;float xminTexture, xmaxTexture;float yminTexture, ymaxTexture;glm::vec2 selectPixel;glm::vec2 selectPixelInTexture = glm::vec2(0);float scale = 1.0;int scaleLevel = 0; // 图片的放大倍率 实际放大的倍数是pow(1.25, scale) 对应图片的面积大小就是pow(0.8, scale);glm::vec2 offset = glm::vec2(0, 0);int rows = 0, cols = 0; // 图像分辨率 不会随着滚轮放缩图像而改变int imgType = CV_8UC1;cv::Mat pic;private:void updateRoi();cv::Point roiPt1, roiPt2;glm::vec2 mousePos;// RenderStateGLuint VAO, VBO;// 渲染窗口的尺寸int screenWidth, screenHeight;int width, height; // 窗口的尺寸 显示图像的Viewport的尺寸glm::ivec2 pos; // 窗口的左上角坐标int textureId = 0;
};BigImageRenderer.cpp
#include"resource_manager.h"
#include"Texture2D.h"using namespace std;void BigImageRenderer::setFileInfo(std::string path)
{filepath = path;int flag1 = path.find_last_of('\\');int flag2 = path.find_last_of('/');if (flag1 == -1 && flag2 == -1){locFolder = "";filename = path;}else{int flag = std::max(flag1, flag2);locFolder = path.substr(0, flag);filename = path.substr(flag + 1, path.length() - flag);}cout << "filepath = " << filepath << endl;cout << "filename = " << filename << endl;cout << "locFolder = " << locFolder << endl;
}BigImageRenderer::BigImageRenderer()
{VAO = 0;VBO = 0;
}void BigImageRenderer::init(glm::ivec2 pos, glm::ivec2 size, GLint textureId, int screenW, int screenH)
{screenWidth = ((screenW == 0) ? size.x : screenW);screenHeight = ((screenH == 0) ? size.y : screenH);glViewport(pos.x, pos.y, width, height);this->pos = pos;width = size.x;height = size.y;this->shader = ResourceManager::LoadShader("shaders\\bigimage.vert","shaders\\bigimage.frag", nullptr, "bigimage");this->shader.use();//shader.setVec2("offset", glm::vec2(0, 0));//shader.setFloat("scale", 1.0f);//shader.setInt("texture1", textureId);this->textureId = textureId;float vertices[] = {// 位置 // 纹理坐标0.0f, 0.0f, 0.0f, 0.0f, // 左下1.0f, 0.0f, 1.0f, 0.0f, // 右下0.0f, 1.0f, 0.0f, 1.0f, // 左上1.0f, 1.0f, 1.0f, 1.0f // 右上};glGenVertexArrays(1, &this->VAO);glGenBuffers(1, &this->VBO);glBindVertexArray(this->VAO);glBindBuffer(GL_ARRAY_BUFFER, this->VBO);glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);// position attributeglVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0);glEnableVertexAttribArray(0);glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)(2 * sizeof(float)));glEnableVertexAttribArray(1);glBindBuffer(GL_ARRAY_BUFFER, 0);glBindVertexArray(0);float ratio = float(size.x) / size.y;// 更新投影矩阵scope.minX = 0.5f - ratio / 2.0f;scope.maxX = 0.5f + ratio / 2.0f;scope.minY = 0.0f;scope.maxY = 1.0f;updateProjectionMatrix();// 更新视图矩阵 (平移和缩放)view = glm::mat4(1.0f);view = glm::translate(view, glm::vec3(-viewPosition.x, -viewPosition.y, 0.0f));view = glm::scale(view, glm::vec3(zoomLevel, zoomLevel, 1.0f));//glBindBuffer(GL_ARRAY_BUFFER, 0);//glBindVertexArray(0);
}void BigImageRenderer::loadData(const cv::Mat &data)
{pic = loadTexture(texture, data);
}void BigImageRenderer::RenderPattern(bool updateViewport/* = true*/)
{// Activate corresponding render stateif(updateViewport)glViewport(pos.x, pos.y, width, height);//glClearColor(0.3, 0.3, 0.3, 1.0);清除颜色缓冲区//glClear(GL_COLOR_BUFFER_BIT);GLboolean blendEnabled = glIsEnabled(GL_BLEND);glDisable(GL_BLEND);shader.use();shader.setMat4("projection", projection);shader.setMat4("view", view);shader.setInt("imgType", imgType);shader.setInt("imageTexture", 0);//std::lock_guard<std::mutex> lock(tileMutex);for (const auto& tile : tiles){if (tile.loaded){// 计算模型矩阵 (位置和缩放)glm::mat4 model = glm::mat4(1.0f);if (imageRatio > 1.0f) // 胖型，优先保证X方向，Y方向 / imageRatio{model = glm::translate(model, glm::vec3(tile.x / (float)cols,tile.y / (float)rows / imageRatio,0.0f));model = glm::scale(model, glm::vec3(tile.width / (float)cols,tile.height / (float)rows / imageRatio,1.0f));}else // 瘦型，优先保证Y方向, X方向*imageRatio{model = glm::translate(model, glm::vec3(tile.x / (float)cols * imageRatio,tile.y / (float)rows,0.0f));model = glm::scale(model, glm::vec3(tile.width / (float)cols * imageRatio,tile.height / (float)rows,1.0f));}shader.setMat4("model", model);//auto n1 = projection * model * glm::vec4(1, 1, 0, 1);//auto n2 = projection * model * glm::vec4(-1, -1, 0, 1);auto n1 = projection * /*view * model **/ glm::vec4(1, 1, 0, 1);auto n2 = projection * /*view * model **/ glm::vec4(-1, -1, 0, 1);glActiveTexture(GL_TEXTURE0);glBindTexture(GL_TEXTURE_2D, tile.textureID);glBindVertexArray(VAO);glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);}
}shader.disable();
}BigImageRenderer::~BigImageRenderer()
{if (VAO){glDeleteVertexArrays(1, &VAO);glDeleteBuffers(1, &VBO);} for (auto& tile : tiles){if (tile.loaded){glDeleteTextures(1, &tile.textureID);}}
}// 创建图像分块
void BigImageRenderer::createTiles()
{int tilesX = (cols + tileSize - 1) / tileSize;int tilesY = (rows + tileSize - 1) / tileSize;tiles.resize(tilesX * tilesY);for (int y = 0; y < tilesY; ++y) {for (int x = 0; x < tilesX; ++x) {int idx = y * tilesX + x;tiles[idx].x = x * tileSize;tiles[idx].y = y * tileSize;tiles[idx].width = std::min(tileSize, cols - x * tileSize);tiles[idx].height = std::min(tileSize, rows - y * tileSize);tiles[idx].loaded = false;}}
}// 加载可见区域的纹理块
void BigImageRenderer::loadVisibleTiles()
{// 计算当前可见区域glm::vec2 visibleMin = viewPosition - glm::vec2(1.0f / zoomLevel);glm::vec2 visibleMax = viewPosition + glm::vec2(1.0f / zoomLevel);//std::lock_guard<std::mutex> lock(tileMutex);for (auto& tile : tiles) {// 检查块是否在可见区域内glm::vec2 tileMin(tile.x / (float)cols, tile.y / (float)rows);glm::vec2 tileMax((tile.x + tile.width) / (float)cols,(tile.y + tile.height) / (float)rows);bool isVisible = !(tileMax.x < visibleMin.x || tileMin.x > visibleMax.x ||tileMax.y < visibleMin.y || tileMin.y > visibleMax.y);if (isVisible && !tile.loaded) {loadTile(tile);}else if (!isVisible && tile.loaded) {// 可选: 卸载不可见块以节省内存// glDeleteTextures(1, &tile.textureID);// tile.loaded = false;}}
}// 加载单个纹理块
void BigImageRenderer::loadTile(ImageTile& tile)
{// 这里应该是实际的图像加载代码// 示例使用空白纹理代替cv::Mat tmpImg = imgGray(cv::Rect(tile.x, tile.y, tile.width, tile.height)).clone();if (tile.textureID == UNDEFINED_TEXTURE){glGenTextures(1, &tile.textureID);}glBindTexture(GL_TEXTURE_2D, tile.textureID);// 为8位灰度或32位浮点图像设置适当的格式if (imgType == CV_8UC1){glTexImage2D(GL_TEXTURE_2D, 0, GL_R8,tile.width, tile.height, 0,GL_RED, GL_UNSIGNED_BYTE, tmpImg.data);}else if (imgType == CV_8UC3){glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8,tile.width, tile.height, 0,GL_RGB, GL_UNSIGNED_BYTE, tmpImg.data);}else if (imgType == CV_32FC3){glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F,tile.width, tile.height, 0,GL_RGB, GL_FLOAT, tmpImg.data);}else if(imgType == CV_32FC1){glTexImage2D(GL_TEXTURE_2D, 0, GL_R32F,tile.width, tile.height, 0,GL_RED, GL_FLOAT, tmpImg.data);}// 设置纹理参数glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);tile.loaded = true;
}void BigImageRenderer::setMousePos(const float &posx, const float &posy)
{//printf("xpos = %f ypos = %f\n", posx, posy);float tmpY = screenHeight - 1.0f - posy;// 如果在窗体内，那么就更新鼠标的位置if (posx >= this->pos.x && posx < this->pos.x + width&& tmpY >= this->pos.y && tmpY < this->pos.y + height){mousePos = glm::vec2(posx, tmpY);}
}void BigImageRenderer::copyROI(BigImageRenderer* render)
{if (this->rows != render->rows || this->cols != render->cols)return;this->scope = render->scope;updateProjectionMatrix();
}void BigImageRenderer::zoomIn()
{float x_ndc = 2.0 * (mousePos.x - pos.x) / (float)width - 1.0f;float y_ndc = 2.0 * (mousePos.y - pos.y) / (float)height - 1.0f;auto pos_scope = glm::inverse(projection) * glm::vec4(x_ndc, -y_ndc, 0.0f, 1.0f);scope.minX = pos_scope.x - (pos_scope.x - scope.minX) * 0.8;scope.minY = pos_scope.y - (pos_scope.y - scope.minY) * 0.8;scope.maxX = pos_scope.x + (scope.maxX - pos_scope.x) * 0.8;scope.maxY = pos_scope.y + (scope.maxY - pos_scope.y) * 0.8;updateProjectionMatrix();
}void BigImageRenderer::zoomOut()
{float x_ndc = 2.0 * (mousePos.x - pos.x) / (float)width - 1.0f;float y_ndc = 2.0 * (mousePos.y - pos.y) / (float)height - 1.0f;auto pos_scope = glm::inverse(projection) * glm::vec4(x_ndc, -y_ndc, 0.0f, 1.0f);scope.minX = pos_scope.x - (pos_scope.x - scope.minX) * 1.25;scope.minY = pos_scope.y - (pos_scope.y - scope.minY) * 1.25;scope.maxX = pos_scope.x + (scope.maxX - pos_scope.x) * 1.25;scope.maxY = pos_scope.y + (scope.maxY - pos_scope.y) * 1.25;updateProjectionMatrix();
}bool BigImageRenderer::isInWindow(const glm::vec2 &pos, bool updateActiveStatus/* = false*/)
{float tmpY = screenHeight - 1.0f - pos.y;//printf("tmpY = %f \n pos.y = %f \n", tmpY, pos.y); //tmpY上大，下小bool flag = false;if (pos.x >= this->pos.x && pos.x < this->pos.x + width&& tmpY >= this->pos.y && tmpY < this->pos.y + height){flag = true;}elseflag = false;if (updateActiveStatus){active = flag;}return flag;
}void BigImageRenderer::updateOffset(const float &offsetX, const float &offsetY)
{scope.minX = scope.minX - offsetX / width * scope.xspan;scope.maxX = scope.maxX - offsetX / width * scope.xspan;scope.minY = scope.minY + offsetY / height * scope.yspan;scope.maxY = scope.maxY + offsetY / height * scope.yspan;updateProjectionMatrix();
}glm::vec3 BigImageRenderer::queryValue(const float &x, const float &y)
{if (imgGray.data == NULL)return glm::vec3(-1.0f, -1.0f, -1.0f);float tmpy = screenHeight - 1.0f - y;float x_ndc = (x - pos.x) / (float)width * 2.0f - 1.0f;float y_ndc = (tmpy - pos.y) / (float)height * 2.0f - 1.0f;auto pos_normal = glm::inverse(projection * view) * glm::vec4(x_ndc, -y_ndc, 0.0f, 1.0f);int row = 0, col = 0;if (imageRatio > 1.0f) // 胖型，优先保证X方向，Y方向 / imageRatio{row = pos_normal.y * imageRatio * rows ; //+ rows;col = pos_normal.x * cols;}else // 瘦型，优先保证Y方向, X方向*imageRatio{row = pos_normal.y * rows; //+ rows;col = pos_normal.x / imageRatio * cols;}selectPixel = glm::vec2(col, row);if (imgGray.empty())return glm::vec3(0);if (row < 0 || row >= imgGray.rows || col < 0 || col >= imgGray.cols)return glm::vec3(0);if (imgGray.type() == CV_8UC3){cv::Vec3b val = imgGray.at<cv::Vec3b>(row, col);return glm::vec3(val[2], val[1], val[0]);}else if (imgGray.type() == CV_8UC1){uchar val = imgGray.at<uchar>(row, col);return glm::vec3(val, val, val);}else if(imgGray.type() == CV_32FC1){float val = imgGray.at<float>(row, col);return glm::vec3(val, val, val);}else if (imgGray.type() == CV_32FC3){float r = imgGray.at<cv::Vec3f>(row, col)[0];float g = imgGray.at<cv::Vec3f>(row, col)[1];float b = imgGray.at<cv::Vec3f>(row, col)[2];return glm::vec3(r, g, b);}
}glm::vec3 BigImageRenderer::queryPixelValue(glm::vec2 pixel)
{selectPixel = pixel;if ((int)selectPixel.x >= imgGray.cols || (int)selectPixel.x < 0 || (int)selectPixel.y >= imgGray.rows || (int)selectPixel.y < 0)return glm::vec3(-1.0f, -1.0f, -1.0f);if (imgGray.type() == CV_8UC3){cv::Vec3b val = imgGray.at<cv::Vec3b>((int)selectPixel.y, (int)selectPixel.x);return glm::vec3(val[2], val[1], val[0]);}else if (imgGray.type() == CV_8UC1){uchar val = imgGray.at<uchar>((int)selectPixel.y, (int)selectPixel.x);return glm::vec3(val, val, val);}else if (imgGray.type() == CV_32FC1){float val = imgGray.at<float>((int)selectPixel.y, (int)selectPixel.x);return glm::vec3(val, val, val);}
}void BigImageRenderer::updateRoi()
{glm::vec2 tl = queryImageCoord(pos.x, screenHeight - (pos.y + height));glm::vec2 br = queryImageCoord(pos.x + width-1.0f, screenHeight - 1.0f - pos.y);if (tl.x == -1.0f && tl.y == -1.0f) return;if (br.x == -1.0f && br.y == -1.0f) return;rowMin = std::min(std::max(0, (int)tl.y), imgGray.rows - 1);rowMax = std::min(std::max(0, (int)br.y), imgGray.rows - 1);colMin = std::min(std::max(0, (int)tl.x), imgGray.cols - 1);colMax = std::min(std::max(0, (int)br.x), imgGray.cols - 1);float x1 = tl.x / (float)pic.cols;float y1 = (pic.rows - tl.y) / (float)pic.rows;float x2 = br.x / (float)pic.cols;float y2 = (pic.rows - br.y) / (float)pic.rows;xminTexture = std::min(std::max(0.0f, std::min(x1, x2)), 1.0f);xmaxTexture = std::min(std::max(0.0f, std::max(x1, x2)), 1.0f);yminTexture = std::min(std::max(0.0f, std::min(y1, y2)), 1.0f);ymaxTexture = std::min(std::max(0.0f, std::max(y1, y2)), 1.0f);
}void BigImageRenderer::updateRoi(double xpos, double ypos)
{if (imgGray.data == NULL)return;float tmpy = screenHeight - 1.0f - ypos;// float转int时强制向下取整int row = pic.rows - ((tmpy - pos.y) / (float)height*scale + offset.y) * pic.rows;int col = ((xpos - pos.x) / (float)width*scale + offset.x) * pic.cols;//printf("row = %d col = %d\n", row, col);roiPt2 = cv::Point(col, row);int w = abs(roiPt2.x - roiPt1.x) + 1;int h = abs(roiPt2.y - roiPt1.y) + 1;int tlx = std::min(roiPt1.x, roiPt2.x);int tly = std::min(roiPt1.y, roiPt2.y);roiMask = cv::Mat::zeros(imgGray.size(), CV_8UC1);roiMask(cv::Rect(tlx, tly, w, h)).setTo(255);
}void BigImageRenderer::updateImg(const cv::Mat &img, const bool &flipY/* = true*/)
{if(img.empty())return ;rowMin = 0; rowMax = img.rows-1;colMin = 0; colMax = img.cols - 1;xminTexture = 0; xmaxTexture = 1.0f;yminTexture = 0; ymaxTexture = 1.0f;imgGray = img.clone();rows = imgGray.rows;cols = imgGray.cols;imageRatio = (float)cols / (float)rows;imgType = img.type();createTiles();loadVisibleTiles();
}glm::vec2 BigImageRenderer::convert2RenderCS(glm::vec2 uv)
{float gx = ((float)(uv.x + 0.5) / pic.cols - offset.x) / scale *2.0 - 1.0;float gy = ((float)(pic.rows - (uv.y + 0.5)) / pic.rows - offset.y) / scale *2.0 - 1.0;return glm::vec2(gx, gy);
}std::vector<glm::vec2> BigImageRenderer::convert2RenderCS(std::vector<glm::vec2> uv)
{std::vector<glm::vec2> result;for (auto p : uv){result.push_back(convert2RenderCS(p));}return result;
}void BigImageRenderer::setRenderUsePseudoColor(bool flag)
{usePseudoColor = flag;
}void BigImageRenderer::updateProjectionMatrix()
{scope.xspan = scope.maxX - scope.minX;scope.yspan = scope.maxY - scope.minY;projection = glm::ortho(scope.minX, scope.maxX, scope.minY, scope.maxY, -1.0f, 1.0f);
}void BigImageRenderer::updateRenderParas()
{shader.use();shader.setVec2("offset", offset);shader.setFloat("scale", scale);
}void BigImageRenderer::reset()
{scaleLevel = 0;scale = 1.0;offset = glm::vec2(0, 0);shader.use();
}void BigImageRenderer::initSelectRoi(double xpos, double ypos)
{isSelectingRoi = true;if (imgGray.data == NULL)return;float tmpy = screenHeight - 1.0f - ypos;// float转int时强制向下取整int row = pic.rows - ((tmpy - pos.y) / (float)height*scale + offset.y) * pic.rows;int col = ((xpos - pos.x) / (float)width*scale + offset.x) * pic.cols;//printf("row = %d col = %d\n", row, col);roiPt1 = cv::Point(col, row);
}// 返回图像的像素坐标
glm::vec2 BigImageRenderer::queryImageCoord(const float &xpos, const float &ypos)
{if (!isInWindow(glm::vec2(xpos, ypos)))return glm::vec2(-1.0f, -1.0f);float tmpy = screenHeight - 1.0f - ypos;float row = pic.rows - ((tmpy - pos.y) / (float)height*scale + offset.y) * pic.rows;float col = ((xpos - pos.x) / (float)width*scale + offset.x) * pic.cols;//printf("ROW = %d COL = %d\n", row, col);selectPixel = glm::vec2(col, row);selectPixelInTexture = glm::vec2(col / (float)pic.cols, (pic.rows - row) / (float)pic.rows);return glm::vec2(col, row);
}void BigImageRenderer::setNormalizeRange( const float &low, const float &high )
{shader.use();shader.setVec2("normalizeRange", low, high);
}