[Scummvm-git-logs] scummvm master -> 7cf428776e43e7ff7c4904dc3698a80d7049d3ec

[neuromancer]

This automated email contains information about 1 new commit which have been
pushed to the 'scummvm' repo located at https://api.github.com/repos/scummvm/scummvm .

Summary:
7cf428776e FREESCAPE: enable thunder effect in DOS with shaders


Commit: 7cf428776e43e7ff7c4904dc3698a80d7049d3ec
    https://github.com/scummvm/scummvm/commit/7cf428776e43e7ff7c4904dc3698a80d7049d3ec
Author: neuromancer (gustavo.grieco at gmail.com)
Date: 2026-03-01T15:07:46+01:00

Commit Message:
FREESCAPE: enable thunder effect in DOS with shaders

Changed paths:
    engines/freescape/games/castle/dos.cpp
    engines/freescape/gfx_opengl_shaders.cpp
    engines/freescape/gfx_opengl_shaders.h


diff --git a/engines/freescape/games/castle/dos.cpp b/engines/freescape/games/castle/dos.cpp
index c7cb608783d..5579106ab21 100644
--- a/engines/freescape/games/castle/dos.cpp
+++ b/engines/freescape/games/castle/dos.cpp
@@ -222,7 +222,14 @@ void CastleEngine::loadAssetsDOSFullGame() {
 			_riddleBottomFrame = loadFrameWithHeaderDOS(stream);
 			_endGameThroneFrame = loadFrameWithHeaderDOS(stream);
 			// No header
-			Graphics::ManagedSurface *thunderFrame = loadFrameFromPlanes(stream, 32, 128);
+			Graphics::ManagedSurface *thunderFrame;
+
+			thunderFrame = loadFrameFromPlanes(stream, 16, 112);
+			thunderFrame->convertToInPlace(_gfx->_texturePixelFormat, (byte *)&kEGADefaultPalette, 16);
+			_thunderFrames.push_back(thunderFrame);
+
+			stream->seek(-0x160,SEEK_CUR);
+			thunderFrame = loadFrameFromPlanes(stream, 16, 112);
 			thunderFrame->convertToInPlace(_gfx->_texturePixelFormat, (byte *)&kEGADefaultPalette, 16);
 			_thunderFrames.push_back(thunderFrame);
 
diff --git a/engines/freescape/gfx_opengl_shaders.cpp b/engines/freescape/gfx_opengl_shaders.cpp
index 413b9da1f28..b689f982f95 100644
--- a/engines/freescape/gfx_opengl_shaders.cpp
+++ b/engines/freescape/gfx_opengl_shaders.cpp
@@ -202,6 +202,87 @@ void OpenGLShaderRenderer::drawSkybox(Texture *texture, Math::Vector3d camera) {
 	_cubemapShader->unbind();
 }
 
+void OpenGLShaderRenderer::drawThunder(Texture *texture, const Math::Vector3d position, const float size) {
+	OpenGLTexture *glTexture = static_cast<OpenGLTexture *>(texture);
+
+	// Compute eye-space position of the thunder
+	// Convention: matrix(col, row) maps to column-major layout
+	const Math::Matrix4 &mv = _modelViewMatrix;
+	float ex = mv(0,0)*position.x() + mv(1,0)*position.y() + mv(2,0)*position.z() + mv(3,0);
+	float ey = mv(0,1)*position.x() + mv(1,1)*position.y() + mv(2,1)*position.z() + mv(3,1);
+	float ez = mv(0,2)*position.x() + mv(1,2)*position.y() + mv(2,2)*position.z() + mv(3,2);
+
+	// Build billboard model-view with Rz(-90) rotation and eye-space translation
+	// cos(-90) = 0, sin(-90) = -1
+	Math::Matrix4 billboardMV;
+	billboardMV(0, 0) = 0.0f;  billboardMV(0, 1) = -1.0f; billboardMV(0, 2) = 0.0f; billboardMV(0, 3) = 0.0f;
+	billboardMV(1, 0) = 1.0f;  billboardMV(1, 1) = 0.0f;  billboardMV(1, 2) = 0.0f; billboardMV(1, 3) = 0.0f;
+	billboardMV(2, 0) = 0.0f;  billboardMV(2, 1) = 0.0f;  billboardMV(2, 2) = 1.0f; billboardMV(2, 3) = 0.0f;
+	billboardMV(3, 0) = ex;    billboardMV(3, 1) = ey;     billboardMV(3, 2) = ez;   billboardMV(3, 3) = 1.0f;
+
+	// Build MVP using the same pattern as drawSkybox/positionCamera
+	Math::Matrix4 proj = _projectionMatrix;
+	Math::Matrix4 model = billboardMV;
+	proj.transpose();
+	model.transpose();
+	Math::Matrix4 thunderMVP = proj * model;
+	thunderMVP.transpose();
+
+	// Build quad geometry (two triangles)
+	float half = size * 0.5f;
+	float quadVerts[] = {
+		-half, -half, 0.0f,
+		 half, -half, 0.0f,
+		 half,  half, 0.0f,
+		-half, -half, 0.0f,
+		 half,  half, 0.0f,
+		-half,  half, 0.0f,
+	};
+	float quadTexCoords[] = {
+		0.0f, 0.0f,
+		0.0f, 0.72f,
+		1.0f, 0.72f,
+		0.0f, 0.0f,
+		1.0f, 0.72f,
+		1.0f, 0.0f,
+	};
+
+	_cubemapShader->use();
+	_cubemapShader->setUniform("mvpMatrix", thunderMVP);
+
+	// Upload quad vertex data
+	glBindBuffer(GL_ARRAY_BUFFER, _cubemapVertVBO);
+	glBufferData(GL_ARRAY_BUFFER, sizeof(quadVerts), quadVerts, GL_DYNAMIC_DRAW);
+
+	// Upload quad texcoord data
+	glBindBuffer(GL_ARRAY_BUFFER, _cubemapTexCoordVBO);
+	glBufferData(GL_ARRAY_BUFFER, sizeof(quadTexCoords), quadTexCoords, GL_DYNAMIC_DRAW);
+
+	// Bind thunder texture
+	glBindTexture(GL_TEXTURE_2D, glTexture->_id);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+	// Additive blending for glow effect
+	glEnable(GL_BLEND);
+	glBlendFunc(GL_ONE, GL_ONE);
+	glDisable(GL_CULL_FACE);
+
+	// Draw the textured quad
+	glDrawArrays(GL_TRIANGLES, 0, 6);
+
+	// Restore skybox vertex data in the VBO
+	glBindBuffer(GL_ARRAY_BUFFER, _cubemapVertVBO);
+	glBufferData(GL_ARRAY_BUFFER, sizeof(_skyVertices), _skyVertices, GL_DYNAMIC_DRAW);
+
+	// Restore state
+	glDisable(GL_BLEND);
+	glEnable(GL_CULL_FACE);
+	glBindTexture(GL_TEXTURE_2D, 0);
+
+	_cubemapShader->unbind();
+}
+
 void OpenGLShaderRenderer::updateProjectionMatrix(float fov, float aspectRatio, float nearClipPlane, float farClipPlane) {
 	float xmaxValue = nearClipPlane * tan(Math::deg2rad(fov) / 2);
 	float ymaxValue = xmaxValue / aspectRatio;
diff --git a/engines/freescape/gfx_opengl_shaders.h b/engines/freescape/gfx_opengl_shaders.h
index 898bcb362ee..e6fb9d0affc 100644
--- a/engines/freescape/gfx_opengl_shaders.h
+++ b/engines/freescape/gfx_opengl_shaders.h
@@ -96,6 +96,7 @@ public:
 	virtual void renderPlayerShootRay(byte color, const Common::Point &position, const Common::Rect &viewPort) override;
 	void drawCelestialBody(Math::Vector3d position, float radius, uint8 color) override;
 	void drawSkybox(Texture *texture, Math::Vector3d camera) override;
+	void drawThunder(Texture *texture, Math::Vector3d position, float size) override;
 
 	virtual void renderCrossair(const Common::Point &crossairPosition) override;