Add shadowmapping example (#3653)

9 files changed, 489 insertions, 0 deletions

diff --git a/examples/Makefile b/examples/Makefile
index 11669e3a..235deda2 100644
--- a/examples/Makefile
+++ b/examples/Makefile
@@ -560,6 +560,7 @@ SHADERS = \
     shaders/shaders_palette_switch \
     shaders/shaders_postprocessing \
     shaders/shaders_raymarching \
+    shaders/shaders_shadowmap \
     shaders/shaders_shapes_textures \
     shaders/shaders_simple_mask \
     shaders/shaders_spotlight \
diff --git a/examples/Makefile.Web b/examples/Makefile.Web
index a3c2bb72..8bec0645 100644
--- a/examples/Makefile.Web
+++ b/examples/Makefile.Web
@@ -466,6 +466,7 @@ SHADERS = \
     shaders/shaders_palette_switch \
     shaders/shaders_postprocessing \
     shaders/shaders_raymarching \
+    shaders/shaders_shadowmap \
     shaders/shaders_shapes_textures \
     shaders/shaders_simple_mask \
     shaders/shaders_spotlight \
diff --git a/examples/shaders/resources/models/robot.glb b/examples/shaders/resources/models/robot.glb
new file mode 100644
index 00000000..549011e7
--- /dev/null
+++ b/examples/shaders/resources/models/robot.glb
diff --git a/examples/shaders/resources/shaders/glsl120/shadowmap.fs b/examples/shaders/resources/shaders/glsl120/shadowmap.fs
new file mode 100644
index 00000000..668fdeb4
--- /dev/null
+++ b/examples/shaders/resources/shaders/glsl120/shadowmap.fs
@@ -0,0 +1,86 @@
+#version 120
+
+precision mediump float;
+
+// This shader is based on the basic lighting shader
+// This only supports one light, which is directional, and it (of course) supports shadows
+
+// Input vertex attributes (from vertex shader)
+varying in vec3 fragPosition;
+varying in vec2 fragTexCoord;
+//varying in vec4 fragColor;
+varying in vec3 fragNormal;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// Input lighting values
+uniform vec3 lightDir;
+uniform vec4 lightColor;
+uniform vec4 ambient;
+uniform vec3 viewPos;
+
+// Input shadowmapping values
+uniform mat4 lightVP; // Light source view-projection matrix
+uniform sampler2D shadowMap;
+
+uniform int shadowMapResolution;
+
+void main()
+{
+    // Texel color fetching from texture sampler
+    vec4 texelColor = texture2D(texture0, fragTexCoord);
+    vec3 lightDot = vec3(0.0);
+    vec3 normal = normalize(fragNormal);
+    vec3 viewD = normalize(viewPos - fragPosition);
+    vec3 specular = vec3(0.0);
+
+    vec3 l = -lightDir;
+
+    float NdotL = max(dot(normal, l), 0.0);
+    lightDot += lightColor.rgb*NdotL;
+
+    float specCo = 0.0;
+    if (NdotL > 0.0) specCo = pow(max(0.0, dot(viewD, reflect(-(l), normal))), 16.0); // 16 refers to shine
+    specular += specCo;
+
+    vec4 finalColor = (texelColor*((colDiffuse + vec4(specular, 1.0))*vec4(lightDot, 1.0)));
+
+    // Shadow calculations
+    vec4 fragPosLightSpace = lightVP * vec4(fragPosition, 1);
+    fragPosLightSpace.xyz /= fragPosLightSpace.w; // Perform the perspective division
+    fragPosLightSpace.xyz = (fragPosLightSpace.xyz + 1.0f) / 2.0f; // Transform from [-1, 1] range to [0, 1] range
+    vec2 sampleCoords = fragPosLightSpace.xy;
+    float curDepth = fragPosLightSpace.z;
+    // Slope-scale depth bias: depth biasing reduces "shadow acne" artifacts, where dark stripes appear all over the scene.
+    // The solution is adding a small bias to the depth
+    // In this case, the bias is proportional to the slope of the surface, relative to the light
+    float bias = max(0.0008 * (1.0 - dot(normal, l)), 0.00008);
+    int shadowCounter = 0;
+    const int numSamples = 9;
+    // PCF (percentage-closer filtering) algorithm:
+    // Instead of testing if just one point is closer to the current point,
+    // we test the surrounding points as well.
+    // This blurs shadow edges, hiding aliasing artifacts.
+    vec2 texelSize = vec2(1.0f / float(shadowMapResolution));
+    for (int x = -1; x <= 1; x++)
+    {
+        for (int y = -1; y <= 1; y++)
+        {
+            float sampleDepth = texture2D(shadowMap, sampleCoords + texelSize * vec2(x, y)).r;
+            if (curDepth - bias > sampleDepth)
+            {
+                shadowCounter++;
+            }
+        }
+    }
+    finalColor = mix(finalColor, vec4(0, 0, 0, 1), float(shadowCounter) / float(numSamples));
+
+    // Add ambient lighting whether in shadow or not
+    finalColor += texelColor*(ambient/10.0)*colDiffuse;
+
+    // Gamma correction
+    finalColor = pow(finalColor, vec4(1.0/2.2));
+    gl_FragColor = finalColor;
+}
diff --git a/examples/shaders/resources/shaders/glsl120/shadowmap.vs b/examples/shaders/resources/shaders/glsl120/shadowmap.vs
new file mode 100644
index 00000000..bace1d70
--- /dev/null
+++ b/examples/shaders/resources/shaders/glsl120/shadowmap.vs
@@ -0,0 +1,32 @@
+#version 120
+
+// Input vertex attributes
+attribute vec3 vertexPosition;
+attribute vec2 vertexTexCoord;
+attribute vec3 vertexNormal;
+attribute vec4 vertexColor;
+
+// Input uniform values
+uniform mat4 mvp;
+uniform mat4 matModel;
+uniform mat4 matNormal;
+
+// Output vertex attributes (to fragment shader)
+varying vec3 fragPosition;
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+varying vec3 fragNormal;
+
+// NOTE: Add here your custom variables
+
+void main()
+{
+    // Send vertex attributes to fragment shader
+    fragPosition = vec3(matModel*vec4(vertexPosition, 1.0));
+    fragTexCoord = vertexTexCoord;
+    fragColor = vertexColor;
+    fragNormal = normalize(vec3(matNormal*vec4(vertexNormal, 1.0)));
+
+    // Calculate final vertex position
+    gl_Position = mvp*vec4(vertexPosition, 1.0);
+}
diff --git a/examples/shaders/resources/shaders/glsl330/shadowmap.fs b/examples/shaders/resources/shaders/glsl330/shadowmap.fs
new file mode 100644
index 00000000..506b51a8
--- /dev/null
+++ b/examples/shaders/resources/shaders/glsl330/shadowmap.fs
@@ -0,0 +1,86 @@
+#version 330
+
+// This shader is based on the basic lighting shader
+// This only supports one light, which is directional, and it (of course) supports shadows
+
+// Input vertex attributes (from vertex shader)
+in vec3 fragPosition;
+in vec2 fragTexCoord;
+//in vec4 fragColor;
+in vec3 fragNormal;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// Output fragment color
+out vec4 finalColor;
+
+// Input lighting values
+uniform vec3 lightDir;
+uniform vec4 lightColor;
+uniform vec4 ambient;
+uniform vec3 viewPos;
+
+// Input shadowmapping values
+uniform mat4 lightVP; // Light source view-projection matrix
+uniform sampler2D shadowMap;
+
+uniform int shadowMapResolution;
+
+void main()
+{
+    // Texel color fetching from texture sampler
+    vec4 texelColor = texture(texture0, fragTexCoord);
+    vec3 lightDot = vec3(0.0);
+    vec3 normal = normalize(fragNormal);
+    vec3 viewD = normalize(viewPos - fragPosition);
+    vec3 specular = vec3(0.0);
+
+    vec3 l = -lightDir;
+
+    float NdotL = max(dot(normal, l), 0.0);
+    lightDot += lightColor.rgb*NdotL;
+
+    float specCo = 0.0;
+    if (NdotL > 0.0) specCo = pow(max(0.0, dot(viewD, reflect(-(l), normal))), 16.0); // 16 refers to shine
+    specular += specCo;
+
+    finalColor = (texelColor*((colDiffuse + vec4(specular, 1.0))*vec4(lightDot, 1.0)));
+
+    // Shadow calculations
+    vec4 fragPosLightSpace = lightVP * vec4(fragPosition, 1);
+    fragPosLightSpace.xyz /= fragPosLightSpace.w; // Perform the perspective division
+    fragPosLightSpace.xyz = (fragPosLightSpace.xyz + 1.0f) / 2.0f; // Transform from [-1, 1] range to [0, 1] range
+    vec2 sampleCoords = fragPosLightSpace.xy;
+    float curDepth = fragPosLightSpace.z;
+    // Slope-scale depth bias: depth biasing reduces "shadow acne" artifacts, where dark stripes appear all over the scene.
+    // The solution is adding a small bias to the depth
+    // In this case, the bias is proportional to the slope of the surface, relative to the light
+    float bias = max(0.0002 * (1.0 - dot(normal, l)), 0.00002) + 0.00001;
+    int shadowCounter = 0;
+    const int numSamples = 9;
+    // PCF (percentage-closer filtering) algorithm:
+    // Instead of testing if just one point is closer to the current point,
+    // we test the surrounding points as well.
+    // This blurs shadow edges, hiding aliasing artifacts.
+    vec2 texelSize = vec2(1.0f / float(shadowMapResolution));
+    for (int x = -1; x <= 1; x++)
+    {
+        for (int y = -1; y <= 1; y++)
+        {
+            float sampleDepth = texture(shadowMap, sampleCoords + texelSize * vec2(x, y)).r;
+            if (curDepth - bias > sampleDepth)
+            {
+                shadowCounter++;
+            }
+        }
+    }
+    finalColor = mix(finalColor, vec4(0, 0, 0, 1), float(shadowCounter) / float(numSamples));
+
+    // Add ambient lighting whether in shadow or not
+    finalColor += texelColor*(ambient/10.0)*colDiffuse;
+
+    // Gamma correction
+    finalColor = pow(finalColor, vec4(1.0/2.2));
+}
diff --git a/examples/shaders/resources/shaders/glsl330/shadowmap.vs b/examples/shaders/resources/shaders/glsl330/shadowmap.vs
new file mode 100644
index 00000000..f8ec45f1
--- /dev/null
+++ b/examples/shaders/resources/shaders/glsl330/shadowmap.vs
@@ -0,0 +1,32 @@
+#version 330
+
+// Input vertex attributes
+in vec3 vertexPosition;
+in vec2 vertexTexCoord;
+in vec3 vertexNormal;
+in vec4 vertexColor;
+
+// Input uniform values
+uniform mat4 mvp;
+uniform mat4 matModel;
+uniform mat4 matNormal;
+
+// Output vertex attributes (to fragment shader)
+out vec3 fragPosition;
+out vec2 fragTexCoord;
+out vec4 fragColor;
+out vec3 fragNormal;
+
+// NOTE: Add here your custom variables
+
+void main()
+{
+    // Send vertex attributes to fragment shader
+    fragPosition = vec3(matModel*vec4(vertexPosition, 1.0));
+    fragTexCoord = vertexTexCoord;
+    fragColor = vertexColor;
+    fragNormal = normalize(vec3(matNormal*vec4(vertexNormal, 1.0)));
+
+    // Calculate final vertex position
+    gl_Position = mvp*vec4(vertexPosition, 1.0);
+}
diff --git a/examples/shaders/shaders_shadowmap.c b/examples/shaders/shaders_shadowmap.c
new file mode 100644
index 00000000..15ffe008
--- /dev/null
+++ b/examples/shaders/shaders_shadowmap.c
@@ -0,0 +1,251 @@
+/*******************************************************************************************
+*
+*   raylib [shaders] example - Shadowmap
+*
+*   Example originally created with raylib 5.0, last time updated with raylib 5.0
+*
+*   Example contributed by @TheManTheMythTheGameDev and reviewed by Ramon Santamaria (@raysan5)
+*
+*   Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
+*   BSD-like license that allows static linking with closed source software
+*
+********************************************************************************************/
+
+#include "raylib.h"
+#include "raymath.h"
+#include "rlgl.h"
+
+#if defined(PLATFORM_DESKTOP)
+#define GLSL_VERSION            330
+#else   // PLATFORM_ANDROID, PLATFORM_WEB
+#define GLSL_VERSION            120
+#endif
+
+#define SHADOWMAP_RESOLUTION 1024
+
+RenderTexture2D LoadShadowmapRenderTexture(int width, int height);
+void UnloadShadowmapRenderTexture(RenderTexture2D target);
+void DrawScene(Model cube, Model robot);
+
+//------------------------------------------------------------------------------------
+// Program main entry point
+//------------------------------------------------------------------------------------
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const int screenWidth = 800;
+    const int screenHeight = 450;
+
+    SetConfigFlags(FLAG_MSAA_4X_HINT);
+    // Shadows are a HUGE topic, and this example shows an extremely simple implementation of the shadowmapping algorithm,
+    // which is the industry standard for shadows. This algorithm can be extended in a ridiculous number of ways to improve
+    // realism and also adapt it for different scenes. This is pretty much the simplest possible implementation.
+    InitWindow(screenWidth, screenHeight, "raylib [shaders] example - shadowmap");
+
+    Camera3D cam = (Camera3D){ 0 };
+    cam.position = (Vector3){ 10.0f, 10.0f, 10.0f };
+    cam.target = Vector3Zero();
+    cam.projection = CAMERA_PERSPECTIVE;
+    cam.up = (Vector3){ 0.0f, 1.0f, 0.0f };
+    cam.fovy = 45.0f;
+
+    Shader shadowShader = LoadShader(TextFormat("resources/shaders/glsl%i/shadowmap.vs", GLSL_VERSION),
+                                     TextFormat("resources/shaders/glsl%i/shadowmap.fs", GLSL_VERSION));
+    shadowShader.locs[SHADER_LOC_VECTOR_VIEW] = GetShaderLocation(shadowShader, "viewPos");
+    Vector3 lightDir = Vector3Normalize((Vector3){ 0.35f, -1.0f, -0.35f });
+    Color lightColor = WHITE;
+    Vector4 lightColorNormalized = ColorNormalize(lightColor);
+    int lightDirLoc = GetShaderLocation(shadowShader, "lightDir");
+    int lightColLoc = GetShaderLocation(shadowShader, "lightColor");
+    SetShaderValue(shadowShader, lightDirLoc, &lightDir, SHADER_UNIFORM_VEC3);
+    SetShaderValue(shadowShader, lightColLoc, &lightColorNormalized, SHADER_UNIFORM_VEC4);
+    int ambientLoc = GetShaderLocation(shadowShader, "ambient");
+    float ambient[4] = {0.1f, 0.1f, 0.1f, 1.0f};
+    SetShaderValue(shadowShader, ambientLoc, ambient, SHADER_UNIFORM_VEC4);
+    int lightVPLoc = GetShaderLocation(shadowShader, "lightVP");
+    int shadowMapLoc = GetShaderLocation(shadowShader, "shadowMap");
+    int shadowMapResolution = SHADOWMAP_RESOLUTION;
+    SetShaderValue(shadowShader, GetShaderLocation(shadowShader, "shadowMapResolution"), &shadowMapResolution, SHADER_UNIFORM_INT);
+
+    Model cube = LoadModelFromMesh(GenMeshCube(1.0f, 1.0f, 1.0f));
+    cube.materials[0].shader = shadowShader;
+    Model robot = LoadModel("resources/models/robot.glb");
+    for (int i = 0; i < robot.materialCount; i++)
+    {
+        robot.materials[i].shader = shadowShader;
+    }
+    int animCount = 0;
+    ModelAnimation* robotAnimations = LoadModelAnimations("resources/models/robot.glb", &animCount);
+
+    RenderTexture2D shadowMap = LoadShadowmapRenderTexture(SHADOWMAP_RESOLUTION, SHADOWMAP_RESOLUTION);
+    // For the shadowmapping algorithm, we will be rendering everything from the light's point of view
+    Camera3D lightCam = (Camera3D){ 0 };
+    lightCam.position = Vector3Scale(lightDir, -15.0f);
+    lightCam.target = Vector3Zero();
+    // Use an orthographic projection for directional lights
+    lightCam.projection = CAMERA_ORTHOGRAPHIC;
+    lightCam.up = (Vector3){ 0.0f, 1.0f, 0.0f };
+    lightCam.fovy = 20.0f;
+
+    SetTargetFPS(60);
+    //--------------------------------------------------------------------------------------
+    int fc = 0;
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        float dt = GetFrameTime();
+
+        Vector3 cameraPos = cam.position;
+        SetShaderValue(shadowShader, shadowShader.locs[SHADER_LOC_VECTOR_VIEW], &cameraPos, SHADER_UNIFORM_VEC3);
+        UpdateCamera(&cam, CAMERA_ORBITAL);
+
+        fc++;
+        fc %= (robotAnimations[0].frameCount);
+        UpdateModelAnimation(robot, robotAnimations[0], fc);
+
+        const float cameraSpeed = 0.05f;
+        if (IsKeyDown(KEY_LEFT))
+        {
+            if (lightDir.x < 0.6f)
+                lightDir.x += cameraSpeed * 60.0f * dt;
+        }
+        if (IsKeyDown(KEY_RIGHT))
+        {
+            if (lightDir.x > -0.6f)
+                lightDir.x -= cameraSpeed * 60.0f * dt;
+        }
+        if (IsKeyDown(KEY_UP))
+        {
+            if (lightDir.z < 0.6f)
+                lightDir.z += cameraSpeed * 60.0f * dt;
+        }
+        if (IsKeyDown(KEY_DOWN))
+        {
+            if (lightDir.z > -0.6f)
+                lightDir.z -= cameraSpeed * 60.0f * dt;
+        }
+        lightDir = Vector3Normalize(lightDir);
+        lightCam.position = Vector3Scale(lightDir, -15.0f);
+        SetShaderValue(shadowShader, lightDirLoc, &lightDir, SHADER_UNIFORM_VEC3);
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+        // First, render all objects into the shadowmap
+        // The idea is, we record all the objects' depths (as rendered from the light source's point of view) in a buffer
+        // Anything that is "visible" to the light is in light, anything that isn't is in shadow
+        // We can later use the depth buffer when rendering everything from the player's point of view
+        // to determine whether a given point is "visible" to the light
+
+        // Record the light matrices for future use!
+        Matrix lightView;
+        Matrix lightProj;
+        BeginTextureMode(shadowMap);
+        ClearBackground(WHITE);
+        BeginMode3D(lightCam);
+            lightView = rlGetMatrixModelview();
+            lightProj = rlGetMatrixProjection();
+            DrawScene(cube, robot);
+        EndMode3D();
+        EndTextureMode();
+        Matrix lightViewProj = MatrixMultiply(lightView, lightProj);
+
+        ClearBackground(RAYWHITE);
+
+        SetShaderValueMatrix(shadowShader, lightVPLoc, lightViewProj);
+
+        rlEnableShader(shadowShader.id);
+        int slot = 10; // Can be anything 0 to 15, but 0 will probably be taken up
+        rlActiveTextureSlot(10);
+        rlEnableTexture(shadowMap.depth.id);
+        rlSetUniform(shadowMapLoc, &slot, SHADER_UNIFORM_INT, 1);
+
+        BeginMode3D(cam);
+
+            // Draw the same exact things as we drew in the shadowmap!
+            DrawScene(cube, robot);
+        
+        EndMode3D();
+
+        DrawText("Shadows in raylib using the shadowmapping algorithm!", screenWidth - 320, screenHeight - 20, 10, GRAY);
+        DrawText("Use the arrow keys to rotate the light!", 10, 10, 30, RED);
+
+        EndDrawing();
+
+        if (IsKeyPressed(KEY_F))
+        {
+            TakeScreenshot("shaders_shadowmap.png");
+        }
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+
+    UnloadShader(shadowShader);
+    UnloadModel(cube);
+    UnloadModel(robot);
+    UnloadModelAnimations(robotAnimations, animCount);
+    UnloadShadowmapRenderTexture(shadowMap);
+
+    CloseWindow();        // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}
+
+RenderTexture2D LoadShadowmapRenderTexture(int width, int height)
+{
+    RenderTexture2D target = { 0 };
+
+    target.id = rlLoadFramebuffer(width, height);   // Load an empty framebuffer
+    target.texture.width = width;
+    target.texture.height = height;
+
+    if (target.id > 0)
+    {
+        rlEnableFramebuffer(target.id);
+
+        // Create depth texture
+        // We don't need a color texture for the shadowmap
+        target.depth.id = rlLoadTextureDepth(width, height, false);
+        target.depth.width = width;
+        target.depth.height = height;
+        target.depth.format = 19;       //DEPTH_COMPONENT_24BIT?
+        target.depth.mipmaps = 1;
+
+        // Attach depth texture to FBO
+        rlFramebufferAttach(target.id, target.depth.id, RL_ATTACHMENT_DEPTH, RL_ATTACHMENT_TEXTURE2D, 0);
+
+        // Check if fbo is complete with attachments (valid)
+        if (rlFramebufferComplete(target.id)) TRACELOG(LOG_INFO, "FBO: [ID %i] Framebuffer object created successfully", target.id);
+
+        rlDisableFramebuffer();
+    }
+    else TRACELOG(LOG_WARNING, "FBO: Framebuffer object can not be created");
+
+    return target;
+}
+
+// Unload shadowmap render texture from GPU memory (VRAM)
+void UnloadShadowmapRenderTexture(RenderTexture2D target)
+{
+    if (target.id > 0)
+    {
+        // NOTE: Depth texture/renderbuffer is automatically
+        // queried and deleted before deleting framebuffer
+        rlUnloadFramebuffer(target.id);
+    }
+}
+
+void DrawScene(Model cube, Model robot)
+{
+    DrawModelEx(cube, Vector3Zero(), (Vector3) { 0.0f, 1.0f, 0.0f }, 0.0f, (Vector3) { 10.0f, 1.0f, 10.0f }, BLUE);
+    DrawModelEx(cube, (Vector3) { 1.5f, 1.0f, -1.5f }, (Vector3) { 0.0f, 1.0f, 0.0f }, 0.0f, Vector3One(), WHITE);
+    DrawModelEx(robot, (Vector3) { 0.0f, 0.5f, 0.0f }, (Vector3) { 0.0f, 1.0f, 0.0f }, 0.0f, (Vector3) { 1.0f, 1.0f, 1.0f }, RED);
+}
diff --git a/examples/shaders/shaders_shadowmap.png b/examples/shaders/shaders_shadowmap.png
new file mode 100644
index 00000000..2d180ee7
--- /dev/null
+++ b/examples/shaders/shaders_shadowmap.png